Folding Bikes - large wheels are pointless

After riding folders for a few years I think I can finally say I've concluded that larger than 20" wheels are basically pointless.

Many are familiar with Tony Hadland's table of the advantages/disadvantages of small wheels:

However, almost all the "disadvantages" are either extremely myopic or are grasping at straws:
1. "wheel has less inertia" - there is no possible way this could be interpreted as a disadvantage. If it were a disadvantage then one could simply add lead weights, which would just be stupid.
2. "bumpier ride unless wider tires" - good quality wider tires are better (faster and more comfortable). The only problem that can be attributed to wider tires is that they are heavier, but that doesn't apply if you switch to a smaller wheel because it's canceled by the shorter circumference.
3. "reduced efficiency of rim brakes" - this isn't a disadvantage because you can switch to hub brakes, which would be regarded as superior except that pointlessly large wheels reduce their efficiency
4. "higher bearing friction" - has anyone here ever notice a significant difference by upgrading to lighter bearing grease?
5. "special tire construction needed" - you need good tires on large wheels too.

The only valid complaints are that the cables are longer, things wear a little faster, and they have more rolling resistance on soft ground. The first two are minor complaints compared to the long list of advantages and bicycles are never very good on soft ground anyway (even big wheeled ones), which is why they weren't invented/popularized until after the construction of modern roads.

I'm inclined to agree with Xootr (http://www.xootr.com/swift-folding-bike-wheels.html) that there are really only two cases in which small wheels aren't the superior choice:
-Downhill mountain bike racing. Let's be clear. If you want to go near-vertically down the side of a mountain, you don't want to do that on a bike with 406mm rims. You want to be able to roll over huge boulders and clear giant felled trees. This isn't the bike for that job.
-USCF road racing. The Swift (nor any 406mm-wheeled bike) doesn't meet the precise technical standards of the Luddites in charge of most bicycle racing standards.

There is something to be said for having more inertia. Don't get me wrong, I love my Brompton, it accelerates quickly and is a hoot to fling through traffic. But my tourer, on enormous 700c x38 tyres, just keeps on going like a train. My average speed is always higher on this bike, and it's my pick for the open road.

After having ridden my new mixte for around three weeks now after riding on folders exclusively for almost two years, I can honestly say I prefer the little wheeled bikes better. Don't get me wrong, the mixte is a blast to ride, but I enjoy the foldies and small wheelers more. YMMV though.

After riding folders for a few years I think I can finally say I've concluded that larger than 20" wheels are basically pointless.

General statements like this are generally pointless. I could point to many applications for large bicycle wheels that small 20" wheels would not operate sufficiently well to be acceptable. I have wheel sizes of 16", 20", 26" and 29" in my fleet. I would agree that the 16" and 20" wheels work well for many bicycle applications, but to say wheels larger than 20" are pointless is ridiculous on its face.

There is something to be said for having more inertia. Don't get me wrong, I love my Brompton, it accelerates quickly and is a hoot to fling through traffic. But my tourer, on enormous 700c x38 tyres, just keeps on going like a train. My average speed is always higher on this bike, and it's my pick for the open road.

If that's how you feel then all you need to do is glue some fishing weights to your spokes to increase the inertia. It's not a small wheel thing, it's a lightness thing, but I believe it's safe to say that most people don't think adding weight to a bike will make it better.


General statements like this are generally pointless. I could point to many applications for large bicycle wheels that small 20" wheels would not operate sufficiently well to be acceptable. I have wheel sizes of 16", 20", 26" and 29" in my fleet. I would agree that the 16" and 20" wheels work well for many bicycle applications, but to say wheels larger than 20" are pointless is ridiculous on its face.

What would those applications be apart from mountain/trail biking or USCF racing? For years I've been looking for an excuse to waste a big chunk of money on a big wheeled bike, but I've yet to find a good reason. I'm not saying there aren't bikes with big wheels which provide unique advantages, but just that they'd mostly be better with smaller wheels.

Mountain biking of any type not just downhill racing is certainly one application. Road racing/sport riding when not racing would be a couple more. Touring on rough/poor/unpaved roads. Winter riding. Commuting on poor roads.

You can get around some of the problems with small wheels with suspension, but that adds cost and complexity to the bike so you can't say a large wheeled rigid bike is pointless by comparison.

I use different sized wheel bikes one after the other on a daily basis and there certainly are benefits to small & to larger wheel sizes.

If you wanted to say that for non-competitive use on nicely paved roads you could do almost anything with a small wheeled bike I'd agree, but that doesn't mean large wheels are useless since I could say the same thing for large wheel bikes and they have the benefit of tackling poor roads/dirt roads and off road better.

Mountain biking of any type not just downhill racing is certainly one application. Road racing/sport riding when not racing would be a couple more. Touring on rough/poor/unpaved roads. Winter riding. Commuting on poor roads.

You can get around some of the problems with small wheels with suspension, but that adds cost and complexity to the bike so you can't say a large wheeled rigid bike is pointless by comparison.

I use different sized wheel bikes one after the other on a daily basis and there certainly are benefits to small & to larger wheel sizes.

If you wanted to say that for non-competitive use on nicely paved roads you do almost anything with a small wheeled bike I'd agree, but that doesn't mean large wheels are useless since I could say the same thing for large wheel bikes and they have the benefit of tackling poor roads/dirt roads and off road better.

Suspension tires don't add cost or complexity. As I said in the OP the only argument against wide suspension tires is weight, but small wheels negate it so there's no argument against them at all.

All my riding is on rough, poor roads with a good amount commuting in winter and I don't see what the advantage of larger wheels are. They just make those wide tires I need heavier.

Dirt/off road sure (there are many strange contraptions which are useful in the wilderness), but it's very hard to see any useful purpose in such riding for the 99% of mankind that lives in civilization, hence, larger diameter wheels are pointless. You can't say the same in reverse because small wheels have many advantages while large wheels have only one esoteric advantage at the fringe of a bicycle's capability. If riding off/unpaved road had a point then the bicycle would have been invented shortly after the wheel instead of thousands of years later during the rise of modern civilization.

Large wheels are only have advantage for sport; in other words diversion; in other words pointless.

Ahahahaha ;)

OK, let me preface this by saying that I can fully accept that "large wheels are pointless for makeinu and some other cyclists." 100% on board with that.

Separately, some people just like the ride, feel, convenience, novelty, non-conformity, whatever of small-wheeled bikes. That's also perfectly valid.

And if you're happy with your bikes, then there is absolutely no reason to change.

But.

When comparing "like to like" -- which is, of course, the only rational and fair way to approach the issue -- larger wheeled bikes:
• are more comfortable
• are more stable
• offer better gearing options
• have vastly better ground clearance (for both drive train and panniers)
• offer more fit options (exception for Bike Friday)
• offer more wheel and tire options
• have more widely available parts
• have more frame material options (i.e. currently, no carbon fiber folding / mini-bikes)
• are less expensive

Some of these aspects can be compensated for; e.g. adding suspension makes a small wheeled bike more comfortable. A few aspects cannot be corrected, such as clearance and tire/wheel/parts availability or expense.

More importantly, as with everything in bicycle design (and life ;) ), design choices involve certain compromises -- either in performance or expense. E.g. if you add mechanical suspension to make a 20" bike more comfortable, that adds weight, complexity and slight performance loss. (Also, in order to compare like to like, you must compare the ride of a 20" suspended bike to a 700c suspended bike.) Or, you may need to spend $500 - $1000 more for a almost-no-compromise Bike Friday New World Tourist than you would for a comparably spec'ed 700c touring bike.

I.e. we can add a few things to the "700c is good" list, including: touring, long distance events, commuting, bad weather riding, dirt trails, gravel trails, just about any off-road use, club rides and paceline riding. 20" can be adapted for some of these uses, but at a cost.

20" bikes clearly have their advantages -- for some but not all applications. I would even say that folders are a good choice for a much wider piece of the market than they currently hold, particularly for urban dwellers, commuters and frequent flyer bike tourists. But these benefits -- and your subjective experiences and personal preferences -- hardly renders the needs of 90+% of the cycling public "pointless."

Or to put it another way: In many cases, the compromises involved in using a small-wheeled bike are often worth the benefits. But to pretend there are no compromises whatsoever is inaccurate and does a disservice to those who need to make an honest assessment of the benefits and costs of a 20" wheeled bike for their own uses.

Suspension tires don't add cost or complexity. As I said in the OP the only argument against wide suspension tires is weight, but small wheels negate it so there's no argument against them at all.

All my riding is on rough, poor roads with a good amount commuting in winter and I don't see what the advantage of larger wheels are. They just make those wide tires I need heavier.

Dirt/off road sure (there are many strange contraptions which are useful in the wilderness), but it's very hard to see any useful purpose in such riding for the 99% of mankind that lives in civilization, hence, larger diameter wheels are pointless. You can't say the same in reverse because small wheels have many advantages while large wheels have only one esoteric advantage at the fringe of a bicycle's capability. If riding off/unpaved road had a point then the bicycle would have been invented shortly after the wheel instead of thousands of years later during the rise of modern civilization.

Large wheels are only have advantage for sport; in other words diversion; in other words pointless.

We'll just agree to disagree then.

I like my 20" Dahon a lot but 20" wheels are significantly harsher than larger wheels. My riding style has adjusted a great deal to compensate for this but at some point, when I have the storage space, I'll probably buy a road bike. Anyhow, I'm looking forward to (and assuming that) Big Apple Liteskin tyres will be available soon; I'd like to switch to a 2.35 at the front to absorb shocks better.

You can get a super-everything sport bike for cheaper than a Moulton. That much is hard to get around. It would be interesting to know if the custom sport bike companies like Calfee could make mini-velos though.

Actually Big Apples are kind of expensive as are Greenspeed Scorchers (what are the other small wheel, low rolling resistance, soft tires out there?), and Dr. Moulton didn't have them when he designed his small wheelers. You could probably build a suspension frame in your garage, but I think tire making is way too expensive and high tech for any niche company to get into.

Ahahahaha ;)

OK, let me preface this by saying that I can fully accept that "large wheels are pointless for makeinu and some other cyclists." 100% on board with that.

Separately, some people just like the ride, feel, convenience, novelty, non-conformity, whatever of small-wheeled bikes. That's also perfectly valid.

And if you're happy with your bikes, then there is absolutely no reason to change.

But.

When comparing "like to like" -- which is, of course, the only rational and fair way to approach the issue -- larger wheeled bikes:
• are more comfortable
• are more stable
• offer better gearing options
• have vastly better ground clearance (for both drive train and panniers)
• offer more fit options (exception for Bike Friday)
• offer more wheel and tire options
• have more widely available parts
• have more frame material options (i.e. currently, no carbon fiber folding / mini-bikes)
• are less expensive

Some of these aspects can be compensated for; e.g. adding suspension makes a small wheeled bike more comfortable. A few aspects cannot be corrected, such as clearance and tire/wheel/parts availability or expense.

More importantly, as with everything in bicycle design (and life ;) ), design choices involve certain compromises -- either in performance or expense. E.g. if you add mechanical suspension to make a 20" bike more comfortable, that adds weight, complexity and slight performance loss. (Also, in order to compare like to like, you must compare the ride of a 20" suspended bike to a 700c suspended bike.) Or, you may need to spend $500 - $1000 more for a almost-no-compromise Bike Friday New World Tourist than you would for a comparably spec'ed 700c touring bike.

I.e. we can add a few things to the "700c is good" list, including: touring, long distance events, commuting, bad weather riding, dirt trails, gravel trails, just about any off-road use, club rides and paceline riding. 20" can be adapted for some of these uses, but at a cost.

20" bikes clearly have their advantages -- for some but not all applications. I would even say that folders are a good choice for a much wider piece of the market than they currently hold, particularly for urban dwellers, commuters and frequent flyer bike tourists. But these benefits -- and your subjective experiences and personal preferences -- hardly renders the needs of 90+% of the cycling public "pointless."

Or to put it another way: In many cases, the compromises involved in using a small-wheeled bike are often worth the benefits. But to pretend there are no compromises whatsoever is inaccurate and does a disservice to those who need to make an honest assessment of the benefits and costs of a 20" wheeled bike for their own uses.

The thing is, half of your claims are just plain false and the other half aren't comparing like for like. In particular:
• Larger wheels do not necessarily offer better gearing options. Notably the Sturmey Archer 8 speed is, IMO, the best gearing choice for the money and is distinctly unsuitable for larger wheels. Moreover, when it comes to complete bikes internally hubbed configurations (with any model) are extremely difficult to find with large wheels despite being the most common configuration for smaller wheels.
• Smaller wheels offer more fit options, not the other way around. Larger wheeled bikes are necessarily limited in fit due to the wheels (and supporting tubes) getting in the way of raising/lowering seat and handlebar posts. To compensate, larger wheeled bikes must offer different frame sizes, which is by its very nature more limiting and a bit of a kludge. Companies like Bike Friday which can accommodate both methods offer the most options of all, but such flexibility is of course exclusive to small wheels.
• Nothing offers better ground clearance for luggage than small wheels which can accommodate on top. The very necessity of panniers with larger wheels is a compromise which reduces ground clearance. All the serious cargo bikes such as those available from Worksman and Bakfiets use smaller wheels because the load carrying capability is simply superior.
• 406 bmx wheels and tires are more widely available than any other rim size. I bet almost every local toy store, hardware store, and, bike store in the world has them.
• Which is less expensive really depends on the kind of configuration you like and may be regarded as merely coincidental. Larger wheeled bikes certainly aren't always less expensive. I can't find a 17 pound bike with larger wheels than the Carryme and I certainly can't find a cheaper trike of comparable weight to the Carryall.
• In order to compare like for like we need to look at wheels of the same weight. Since larger diameter tires are so much heavier they need to be much skinnier in order to achieve the same weight. This makes them less comfortable and compromises performance. Also, as noted by Tony Hadland suspension is easier/lighter to implement with smaller wheels (and wide tires may be regarded as a special case of this). So, although you can compare unsuspended to unsuspended, it's not really a like for like comparison because the parameters of importance such as complexity, weight, etc are not equal. Thus, when comparing like for like on the important parameters of complexity, weight, etc smaller wheeled bikes are more comfortable.

I'm not trying to be belligerent here, but your arguments simply don't hold any water.

Now, yes, there are a few very specialist applications for which factors make small wheeled bikes inferior. These are, namely, riding off paved roads and competitions for which small wheels are simply disallowed. However, as I've said from the beginning, these applications are by their very nature pointless and, thus, the large wheeled bikes which they justify are also pointless.

In all other applications small wheelers are unequivocally superior. Large wheels are the ones making compromises, compromises to keep with the popular look. If you want to convince me otherwise then tell me, what advantages do large wheels have? I still haven't seen any apart from wear and riding on soft ground, which is a short list compared to all their many disadvantages. Your so used to making compromises to accommodate large wheels that you can't see the forest from the trees.

I like my 20" Dahon a lot but 20" wheels are significantly harsher than larger wheels. My riding style has adjusted a great deal to compensate for this but at some point, when I have the storage space, I'll probably buy a road bike. Anyhow, I'm looking forward to (and assuming that) Big Apple Liteskin tyres will be available soon; I'd like to switch to a 2.35 at the front to absorb shocks better.

I'm not perfectly comfortable on my small wheelers either, but a road bike is not more comfortable and a mountain bike is heavier than a dedicated suspension (not to mention compromises carrying capacity, fine tuning fit, etc).

I just don't understand why people say that small wheels involve compromises when it seems pretty clear that it's the large ones which involve compromises. I tried to believe for a long time that the large ones were somehow better, but it just isn't true (even without considering folding).

As far as I can figure out the historical reasons, wheel size for the safety bicycle was a consideration of comfort and economy. Rough roads which were of course largely unpaved indicated wheels as large as possible, while ergonomics indicated a smaller size. So the "standard" wheel size we have is as large as can be fitted on a safety bicycle with ergonomic condiderations such as the front wheel hitting the feet. Presumably comfort was more important than economy, or economy had a fairly small impact at the time when wheel size was considered. The smaller size also necessitated some gearing system so that you don't have a stupidly fast cadence for reasonable speeds. So the whole development history stemmed from the original wheel size choice.

I haven't checked the dates, but I think at the time, the pneumatic wheel was not yet invented when the safety bicycle was invented, so the large as spossible wheel would have been chosen as of high importance due to solid tyres.

But the advent of the pneumatic tyre to a large extent neutralised the requirement of a large wheel as mathematically shown by me in the small wheel harshness thread. A very modest reduction in inflation pressure results in indistinguishable comfort response between a 16" wheel and a 700c wheel. The reduction in pressure is not so large as to put the tyre into the high rolling resistance region of operation, ie you can get comfort without sacrificing much speed at all.

So with pneumatic tyres, the only argument that can now justify the large wheel size is the one where road surface has a large scale impact on the wheel, ie bumps/holes much larger than the tyre can absorb, or soft surface where the bigger circumference would sink less into the soft surface.

One might argue about stability but I don't buy that one, based on experience backed up by a thorough understanding of the underlying reasons. Stability is much less determined by wheel size than the intricacies of geometry and weight distribution.

The other arguments are spurious, because they are more connected with what's actually available to buy, ie pre-determined by the ubiquity of larger wheels rather than a design necessity. For example, if by some historical accident a 20" wheel had been chosen as the standard, the marketplace, UCI, gearing option etc would all have centered around that size, and the "better gearing options" argument would be stood on its head.

• Larger wheels do not necessarily offer better gearing options....
Most folders come with single front chainrings; standard-sized bikes routinely come with doubles and triples. IH's are superior for some applications (e.g. commuting), but a) are less efficient than derailleurs, and b) are clearly available for lots of large-wheeled bikes anyway. They're mostly more common on folders etc due to clearance issues and target market (commuters) -- or, in the case of the SRAM DualDrive, to make up for certain deficiencies (at a cost, as per usual -- by doubling the complexity of the drive train).



• Smaller wheels offer more fit options, not the other way around.
Sorry, that's BS, with the notable exception of Bike Friday and maybe a few mini-bikes.

The overwhelming majority of 20" bikes are "one size fits all," which clearly offers fewer options than bikes that come in 5-8 sizes, can swap stems, can swap seatposts, can change handlebars, and so forth.

Offering different sizes allows for a huge variation in geometry specs, including top tube length, seat post angle, head tube angle, BB height, and so forth. For example, if you own a Dahon or a Downtube or a Brompton or many other folders, and don't like the reach, you're pretty much screwed.

There's no magic involved in small wheels that makes them "better" for a one size fits all approach; any bike can be made that way. The "one size fits all" is basically a way of covering a broad market with as few frames as possible. Don't confuse that with an advantage.



• Nothing offers better ground clearance for luggage than small wheels which can accommodate on top.
Dude. Seriously. The bottom bracket and entire transmission on a 20" bike is far lower than with any 26" / 700c bike. Putting the luggage up high seriously curtails your carrying capacity and load balancing. Keep in mind, I've toured several times on 20" bikes with different configs.



• Which is less expensive really depends on the kind of configuration you like and may be regarded as merely coincidental. Larger wheeled bikes certainly aren't always less expensive. I can't find a 17 pound bike with larger wheels than the Carryme and I certainly can't find a cheaper trike of comparable weight to the Carryall.
Again, comparing like to like, the ability to fold adds to the price.

E.g. a Bike Friday NWT with Tiagra / Capreo will set you back $2000. That same price will get you an Orbea Onix with a full carbon fiber frame and full 105. Or, for $1000 you can nab a Surly Long Haul Trucker with Tiagra.

Comparing a 17 pound road bike to a Carryme is simply absurd; their functions and uses are completely incompatible. For example, there is no way you could use a Carryme if you're in 70-mile group ride in a paceline and averaging 20mph; and there's no way you can fold up a Pinarello Prince for a multi-modal commute. The comparison is fatuous.



• In order to compare like for like we need to look at wheels of the same weight. Since larger diameter tires are so much heavier they need to be much skinnier in order to achieve the same weight. This makes them less comfortable and compromises performance.
There are numerous techniques available to lighten a wheel, including using a CF rim or tubular tires -- both of which would improve comfort.

It's pretty clear though that a "standard non-aero 32 spoke 451 wheel" will be lighter, harsher, stronger and more aerodynamic than a "standard non-aero 32 spoke 700c wheel." The larger wheel has more material and more flex, and therefore soaks up more vibrations. The larger diameter also reduces the impact of dips and bumps in the road.

Ergo, you have the design process backwards. To compensate for the harsher ride of the small wheel, the designer will use a wider rim, wider tire, and/or lower PSI; or opt for mechanical suspension. (E.g. the Dahon Speed Pro uses a suspension hub and steel frame in combination with high-pressure narrow Stelvio tires.) This provides an acceptable performance hit, as the smaller wheel is faster anyway. Even so, I and many others have found that 406 wheels with wide tires and the same PSI are harsher than 700 x 23c's.

Separately, there is no reason why suspension is "easier to incorporate" with a small wheel; if anything, a smaller fork could mean less travel. Just because some guy wrote it on his website does not make it so. ;)



Now, yes, there are a few very specialist applications for which factors make small wheeled bikes inferior. These are, namely, riding off paved roads and competitions for which small wheels are simply disallowed. However, as I've said from the beginning, these applications are by their very nature pointless and, thus, the large wheeled bikes which they justify are also pointless.
So because you do not participate or enjoy those activities, they are therefore "pointless" for ALL cyclists? That's patently absurd.

Millions of cyclists enjoy off-road cycling. Millions like riding in clubs and fast group rides. Millions like to tour with more stability and comfort than is offered by most folding bikes. Triathletes abound. Pro cycle racing has millions of fans, and there are hundreds of thousands of amateur racers who enjoy the sport.

And tens of millions of ordinary people simply do not need the advantages of a small-wheeled bike. Space is not at a premium; they don't fly with their bikes; they don't need to bring the bike inside buildings.

By the way, there are competitions that allow any wheel size (e.g. triathlons), and yet somehow 700c wheels still dominate. There was even a brief period where triathletes favord 650c wheels due to the theoretical advantages of slightly smaller wheels; in practice, it didn't produce definitive improvements, so riders are almost all back to 700c. If 451 or 406 provided a tangible benefit, I have no doubt the tri community would be all over it like white on rice.



Your so used to making compromises to accommodate large wheels that you can't see the forest from the trees.
...except that I spent about 2 years making compromises riding folding bikes exclusively, and short of dropping $2,000 on a Bike Friday, did everything I could to make them work for me.

Despite the advantages of folding/20" bikes, I have found FOR ME that 700c works better. My 700c bikes are more comfortable; have better gearing; fit better; can ride on any surface; are much better for club rides; and don't take up more space in my tiny apartment than my folders did. Nothing you've said changes the fundamental character of my experiences and nothing renders my cycling activities "pointless."

Am I losing something with 700c? Sure. I can't take my bike on the train during rush hour, and I need to use a car bike rack. I don't miss it -- and if I did, I'd pick up a folding bike without hesitation. At this time, the comfort, fit, performance and versatility advantages make 700c a net benefit for me. And thankfully, I can say that without disparaging the perfectly legitimate and enjoyable cycling activities of millions of people.

I have bicycles in 3 wheel sizes, 451 mm, 559 mm and 622 mm. Most of the times I ride the folding, small wheeled bicycle because of the 342156 reasons we already discussed here.

This issue of "small" wheels vs "big" wheels is discussed once in a while in the Folding Forums. If small wheels are so good and have so many advantages over bigger wheels, why I haven't seen them in major cycling competitions?

I have bicycles in 3 wheel sizes, 451 mm, 559 mm and 622 mm. Most of the times I ride the folding, small wheeled bicycle because of the 342156 reasons we already discussed here.

This issue of "small" wheels vs "big" wheels is discussed once in a while in the Folding Forums. If small wheels are so good and have so many advantages over bigger wheels, why I haven't seen them in major cycling competitions?Because since the day Moultons were shown to have an unfair advantage over big-wheeled bikes, the UCI has declared them and all other bikes that are not roadies, illegal for sanctioned races. In the HPV arena, small wheels dominate for whatever reason, at least demonstrating the fact that wheel size is negligible in performance.

Dude. Seriously. The bottom bracket ..... is far lower than with any 26" / 700c bike. This is incorrect. They are the same height.




There are numerous techniques available to lighten a wheel, including using a CF rim or tubular tires -- both of which would improve comfort.This is incorrect. Comfort is utterly dominated by the tyre. Wheels flexing simply do not have any impact at all. If they flex at all, it is lateral flexing which is bad for pedalling efficiency.



It's pretty clear though that a "standard non-aero 32 spoke 451 wheel" will be lighter, harsher, stronger and more aerodynamic than a "standard non-aero 32 spoke 700c wheel." The larger wheel has more material and more flex, and therefore soaks up more vibrations. The larger diameter also reduces the impact of dips and bumps in the road.Again, tyres completely dominate the equation - larger wheels simply do NOT soak up more vibrations or anything like that. This is simply one of those commonly accepted cycling myths.


.... I and many others have found that 406 wheels with wide tires and the same PSI are harsher than 700 x 23c's.Well first, you simply can't pump a "wide" tyre to the same PSI as a 700cx23; and even if you pumped said tyre to it's maximum rated value, the pneumatic response dominates. Yours is simply a subjective experience of an entire bike but you fail to appreciate that and blame the wheel size alone. Spurious.



Millions of cyclists enjoy off-road cycling. ...... If 451 or 406 provided a tangible benefit, I have no doubt the tri community would be all over it like white on rice.The argument by numbers. Yes, so many people can't be wrong, right? Well they can if that's all that they can buy. Ever tried buying a tri bike with little wheels? Ever seen one even? Market forces dude.

After having some trail time with my Pocket Llama now, I can say that the 20" wheels are adequate for cross country riding in most conditions, and are quite decent off-road in many types of terrain.

They excel in tight maneuvering conditions, and track through most types of terrain quite well.

They fall short in off-road use in the following:

deep mud and sand
larger rocks and obstacles which the smaller wheels will try to strike off, rather than climbing.

The 26" wheels are better than the 20" wheels for true mountain biking, unless you're doing a tight and smooth singletrack. Would I race on 20" wheels? No, I wouldn't. No chance. But they're perfectly adequate for expedition / rough trekking bikes, in my opinion.

(I am using Schwalbe Mow Joe 20x2.0 when off-roading)

The 406mm wheel has proven to me to be perfectly adequate for novice - intermediate cross country riding. Avoid the technical stuff.

I think that in my opinion, i'd continue to use the 20" wheel for my purposes quite readily. The largest difficulty is in finding good tires for heavy trekking. For example, from my favourite tire manufacturer in the 26" wheel, there are a bunch of good rough trekking tires - Schwalbe Marathon Extreme, Plus Tour, XR, Cross.

The closest 20" offering is the standard Marathon. Although there are several comments on the Schwalbe website from people wanting a 20" heavy trekking tire, and there seems to be some interest. One can only hope!

Its too bad the snow came back, I was wanting more rides on the little beast :)

'Large's prolly pretty pointless for lots of us here in the fodl'n bike frorum,
where we just might be a little biased towards liking, or finding things to like, bout things a bit more towards 'small'..

I would simply state that I find the limited advantagers in some circumstances of larger wheels beyound 20" are not great enought to justify a bike that is not multi- modual transportable. I found that my 20" downtube set up as a roadie was quick enought to make buying a road bike unnessary.

JUdging from my experience ,and the Moulton evidence , for road use it least, the debate of wheel size is only worthwhile for competitive cycling. Other than than its a matter of market forces and personel preference.

As for a mountian biking I feel a simular experience would occur with a 20" wheel specialist bike or a converted BMX bike that could fit in to cars easier.

How do FS downtube owners or jetstream owners find the bikes compaire for non preformance riding compaired to their mountian bikes ?

Bacciagalupe: I have re-read the post that I debated some of your points and I am afraid I came across like an idiot. Sorry mate. With all respect. :)

Jur: No sweat. ;) Feel free to edit your post if needed, I'll stick to mechanics & clarifications etc.



This is incorrect. Comfort is utterly dominated by the tyre. Wheels flexing simply do not have any impact at all. If they flex at all, it is lateral flexing which is bad for pedalling efficiency.
Although I accept that tire properties are significant, I'm not sure why you make this claim.

For example, it's widely accepted that smaller wheels are stronger than larger wheels; e.g. 26" are more common on MTB's because of the increased strength. This in turn makes the smaller wheel stiffer. Since you're using the same materials, increased stiffness also increases transmission of vibrations -- as does the lower mass of the wheel, assuming the materials are of the same type. In this respect, "flex is flex" - it doesn't matter which direction the material moves, what matters is how efficiently the "wheel system" dampens vibrations.

Similarly, wheels with fewer spokes also tend to be harsher. The rims need to be stiffer, lacing patterns are different, there are fewer spokes to absorb shock, tension needs to be higher, and so forth.

Separately, the smaller diameter results in a harsher response to bumps, divots and holes in the road. I hope it's quite clear that a sufficiently large enough wheel can cruise over certain sized holes, while a smaller wheel would dip into the same size hole. The angle of attack of a given hole is also harsher, and that may make a difference.

Changing the rim composition has the same effect as changing the frame composition. If you switch to a carbon rim, that material will absorb more vibrations.

If we were dealing with a small change in tire size (e.g. 650c to 700c) and keeping all other properties identical (i.e. same rim composition, same spoke type and count, same lacing pattern etc), I'd agree that alterations in tire properties will overwhelm structural properties. However 700c to 406 is a much bigger change, therefore structure takes on a much larger role.

Or to put it another way: why isn't the mechanical suspension on a Moulton, a Pacific Reach, a Dahon Speed Pro, an Air Friday, or a Birdy utterly superfluous? These are all essentially road bikes, a category which in 700c almost never has mechanical suspension. Why don't 26"/700c folders like the Dahon Jack, the Pacific iF, the Montague CF "Comfort" use suspension? Or from the opposite tack: Why add suspension to ANY non-MTB bike, if all you need to do is lower the PSI of the tire?

Something just doesn't add up about the "it's only the tires" theory.



Well first, you simply can't pump a "wide" tyre to the same PSI as a 700cx23; and even if you pumped said tyre to it's maximum rated value, the pneumatic response dominates. Yours is simply a subjective experience of an entire bike but you fail to appreciate that and blame the wheel size alone. Spurious.
Not really following you here. There are quite a few tire widths that are in the 100psi range for 406. E.g. Stelvios are narrow, Marathon Slicks were a tad wider, Marathon K's are much wider, all are around the same PSI range. With 700c, tire sizes can easily range from 21c to 28c for the same tire and PSI. AFAIK the PSI range doesn't change based on tire size, either.

Also, I'm quite aware that "comfort" will be based on not just wheel size, but the overall design of the bike. One thing that reinforces my experience in that respect is riding a Dahon for about a year or so. That bike in particular had a steel frame (good dampening properties), no top tube (more flex), a long seat post (more flex), a long handle post (yet more flex) a few hinges (even more flex) and a substantial heft (28 lbs). Despite all these structures and properties, the Dahon had a bumpier and harsher ride than several 700c steel road bikes, especially on cobblestones, gravel and dirt roads -- even when comparing 65 PSI tires to 100 PSI 700 x 28c's. I'm not sure what can account for this, other than wheel properties.

You can disregard my subjective experiences -- in which case, all such subjective claims need to be tossed....



The argument by numbers. Yes, so many people can't be wrong, right? Well they can if that's all that they can buy. Ever tried buying a tri bike with little wheels? Ever seen one even? Market forces dude.
You may have misunderstood my point here. I am not saying "more people ride 700c, therefore it's better." I'm pointing out that makeinu is inappropriately disparaging the legitimate cycling purposes, preferences and enjoyment of millions of people solely because he doesn't engage in those activites.

Because since the day Moultons were shown to have an unfair advantage over big-wheeled bikes, the UCI has declared them and all other bikes that are not roadies, illegal for sanctioned races. In the HPV arena, small wheels dominate for whatever reason, at least demonstrating the fact that wheel size is negligible in performance.

Is this definitively true?! Hadn't heard that before

Assuming it's true, I still don't get why the UCI would ban legitimate improvements to the sport. Why don't they ban carbon wheels, or lighter frames or stiffer bottom brackets, or electronic shifting?

Because since the day Moultons were shown to have an unfair advantage over big-wheeled bikes, the UCI has declared them and all other bikes that are not roadies, illegal for sanctioned races. In the HPV arena, small wheels dominate for whatever reason, at least demonstrating the fact that wheel size is negligible in performance.

In response to the red colour, and just like SC answered, I would like to see test results that supports your sentence.

In response to the green colour, Jur, you're right; I forgot completely the UCI issue over here and their limited approach to every bicycle issue.

Is this definitively true?! Hadn't heard that before

Assuming it's true, I still don't get why the UCI would ban legitimate improvements to the sport. Why don't they ban carbon wheels, or lighter frames or stiffer bottom brackets, or electronic shifting?

The UCI has banned a great deal more technological improvements than just bikes like Moultons. Sometimes their bans can be to bring similar bikes in line with each other, but they do stifle a LOT of good engineering.

One the one hand, you can say that its promoting fairness in competition.

On the other, you can note that the UCI is responsible for suppressing a lot of good bicycling engineering.

Beam frame designs like the Trek Y-foil, and of course, recumbents, are all banned from sanctioned events. They also ban variations on more traditional design when they prove to be effective. Take a look at what the UCI did after each of Graeme Obree's wins.

They're quite the tyrants when it comes to upholding the status quo.

There's no magic involved in small wheels that makes them "better" for a one size fits all approach; any bike can be made that way. The "one size fits all" is basically a way of covering a broad market with as few frames as possible. Don't confuse that with an advantage.

You're right, it's not magic. It's simply the fact that a smaller wheel is closer to the bottom bracket and, thus, doesn't need as much tubing to get in the way of where the rider may want to be. It's actually the opposite of magic because two things can't be in the same place at the same time.



Dude. Seriously. The bottom bracket and entire transmission on a 20" bike is far lower than with any 26" / 700c bike. Putting the luggage up high seriously curtails your carrying capacity and load balancing. Keep in mind, I've toured several times on 20" bikes with different configs.

And in what bizzare universe is 26" not higher than 20"? All the world's serious cargo bikes have small wheels. Touring is a joke by comparison. No matter how you slice it the larger the wheel the more the space on top of it is wasted because, as you said, having the luggage high curtails carrying capacity and load balancing. Hanging things by the sides is not affected, unless you're trying to shoe horn the poorly designed equipment from large wheeled bikes onto small wheeled bikes.

That seems to be your big problem here; You're so stuck on large wheels that you insist on using the fixes that work there while ignoring the superior accommodations offered by smaller wheels, even when dealing with smaller wheels. It's like wearing your running shoes to the beach because they worked well for your marathon.



Comparing a 17 pound road bike to a Carryme is simply absurd; their functions and uses are completely incompatible. For example, there is no way you could use a Carryme if you're in 70-mile group ride in a paceline and averaging 20mph; and there's no way you can fold up a Pinarello Prince for a multi-modal commute. The comparison is fatuous.

Again you're showing the same myopic attitude. I didn't say road bike. Find me a 17 pound bike with large wheels that's cheaper than the Carryme. Any kind you like. If light weight large wheeled bikes only come as road bikes then I guess we can chalk it up to superior selection for smaller wheels.

Also look at dutch-style commuters. Here in the US you'll pay more to get one with large wheels.

Obviously we can go back and fourth cherry picking particular configurations and makes, but the point is that on average neither small nor large wheels really seems to be more expensive. It depends, but on average there's no clear winner in this regard.



Separately, the smaller diameter results in a harsher response to bumps, divots and holes in the road. I hope it's quite clear that a sufficiently large enough wheel can cruise over certain sized holes, while a smaller wheel would dip into the same size hole. The angle of attack of a given hole is also harsher, and that may make a difference.

This simply isn't true. Jur demonstrated in another thread quite clearly that the bump response is equal for two sizes at proper inflation pressure. If you want to compare the two then you have to compare like for like and making the pressures equal is not comparing like for like because that means the smaller tire is either lighter or overinflated.



Or to put it another way: why isn't the mechanical suspension on a Moulton, a Pacific Reach, a Dahon Speed Pro, an Air Friday, or a Birdy utterly superfluous? These are all essentially road bikes, a category which in 700c almost never has mechanical suspension. Why don't 26"/700c folders like the Dahon Jack, the Pacific iF, the Montague CF "Comfort" use suspension? Or from the opposite tack: Why add suspension to ANY non-MTB bike, if all you need to do is lower the PSI of the tire?

Something just doesn't add up about the "it's only the tires" theory.

Pneumatic tires are just one way of implementing suspension and all bikes have them. Obviously different implementations have different pros/cons which dictate when it might be better to use one over another.

What doesn't add up is that you refuse to accept that small wheels aren't a liability, but an asset. You're right to point out that pneumatic tire suspension has it's limits, but those limits are dictated primarily by wheel diameter, with smaller diameters being less restricted than larger ones.

Accept the fact that reducing wheel size enhances the capacity of the built in suspension all bikes have and everything adds up.



Not really following you here. There are quite a few tire widths that are in the 100psi range for 406. E.g. Stelvios are narrow, Marathon Slicks were a tad wider, Marathon K's are much wider, all are around the same PSI range. With 700c, tire sizes can easily range from 21c to 28c for the same tire and PSI. AFAIK the PSI range doesn't change based on tire size, either.

Manufacturer rating and actual breakpoints are two different things. Moreover, both are irrelevant because the correct inflation pressure most certainly does change with tire width regardless of whether or not the breakpoint changes. There's a good introduction here (http://sheldonbrown.com/tires.html#pressure) along with a number of scientific articles discussing the phenomena. In short the optimal operating point for bicycle tires seems to be at a 15% drop, which happens at a lower psi for a wider tire.

So comparing like for like, at the same weight and percentage drop smaller wheels are more comfortable.



Also, I'm quite aware that "comfort" will be based on not just wheel size, but the overall design of the bike. One thing that reinforces my experience in that respect is riding a Dahon for about a year or so. That bike in particular had a steel frame (good dampening properties), no top tube (more flex), a long seat post (more flex), a long handle post (yet more flex) a few hinges (even more flex) and a substantial heft (28 lbs). Despite all these structures and properties, the Dahon had a bumpier and harsher ride than several 700c steel road bikes, especially on cobblestones, gravel and dirt roads -- even when comparing 65 PSI tires to 100 PSI 700 x 28c's. I'm not sure what can account for this, other than wheel properties.

How about riding position or crappy tires?



You may have misunderstood my point here. I am not saying "more people ride 700c, therefore it's better." I'm pointing out that makeinu is inappropriately disparaging the legitimate cycling purposes, preferences and enjoyment of millions of people solely because he doesn't engage in those activites.

Nope. I will fully admit that large wheels provide legitimate purposes, preferences, and enjoyment for millions of people. My claim is that the purposes are entirely void of pragmatism in the context of modern civilization and they don't have any legitimate practical advantage apart from mere preference or enjoyment. It has nothing to do with the activities in which I engage (many of which similarly lack legitimate practical advantages).


Is this definitively true?! Hadn't heard that before

Assuming it's true, I still don't get why the UCI would ban legitimate improvements to the sport. Why don't they ban carbon wheels, or lighter frames or stiffer bottom brackets, or electronic shifting?

The UCI has stated many times that their intention is exactly to ban legitimate improvements to the sport in order to emphasize the rider over the bike. However, I'm guessing they have a little more tolerance for things like carbon wheels, lighter frames, etc because these things don't affect interaction between riders by disrupting factors like rhythm, spacing, etc. They have banned certain aero handlebar positions.

In the end it doesn't matter because the UCI is itself pointless and I don't understand why people bring them up in such discussions as if they had any bearing on superior cyclo-engineering.

Also, this is not a folders versus roadie debate. Larged wheeled folders, recumbents, work bikes, etc are all also included.

Bacciagalupe likes to pit his former Dahon versus his 700c bike, which is perfectly valid, but not necessarily relevant to the merits of wheel size for cycling in general.

Abneycat,

Thanks for bringing up Graeme Obree. I just read about his life and bike and founding inspiring.

Is this not the silliest thread ever? Hmmm...

You can't tell me that a 20" wheel is just as comfortable to ride as a 27" of any width you choose.

Say a big pothole is coming up and its 2" deep and 6" from front to back and 6" wide. Roll a 20 in there (any width, make it 4" if you want) and roll a 27" in there. What one drops in faster, stays in longer goes deeper in most potholes and jars the body more?

And then a bump that goes up, say a 2X4, its 2" high, 4" long and goes like 6" from left to right. You ride over it, the 20 bumps up how fast, and falls off how fast, and the 27?

As the diameter increases the rubber on the road part approches a dead flat and the inperfections in the road are more and more absorbed and minimised. Theres something I'm missing.

Abneycat,

Thanks for bringing up Graeme Obree. I just read about his life and bike and founding inspiring.



No top tube - check
Narrow flat close handlebars - check
Singlespeed - check
He doesn't have small wheels, but it's an alternative solution for clearing a narrow bottom bracket (instead of the abnormally high chainstays).

It's practically a Carryme! (and I can vouch that the Carryme works well with a TT saddle)

Also, I'm quite aware that "comfort" will be based on not just wheel size, but the overall design of the bike. One thing that reinforces my experience in that respect is riding a Dahon for about a year or so. That bike in particular had a steel frame (good dampening properties), no top tube (more flex), a long seat post (more flex), a long handle post (yet more flex) a few hinges (even more flex) and a substantial heft (28 lbs). Despite all these structures and properties, the Dahon had a bumpier and harsher ride than several 700c steel road bikes, especially on cobblestones, gravel and dirt roads -- even when comparing 65 PSI tires to 100 PSI 700 x 28c's. I'm not sure what can account for this, other than wheel properties.

I have a similar experience. My 20" Dahon w/ 30 PSI Big Apples bounces off the sharp edge entering my parking lot that my road bike rolls right over. Yet I still agree with the premise of this thread which would maybe be better stated "Wheel size is overrated." Or at least wheel sizes bigger than the largest gap in a drainage grate.

The issue for the majority of us that don't have good bike shops and don't build our own bikes is the one stated in the quote. Whatever conventional bike that fits and is available on the local craigslist in your price range is likely to provide a more pleasant riding experience, probably because they've been refined to the nth degree by bike designers working within the UCI's regulations and the regulations of the marketplace. If the Tour de France was raced on CarryMes maybe my $900 folder would be unequivocally better for riding to work no-hands over poorly maintained roads than my $20 beater 80's Raleigh road bike.

Although I accept that tire properties are significant, I'm not sure why you make this claim.

For example, it's widely accepted that smaller wheels are stronger than larger wheels; e.g. 26" are more common on MTB's because of the increased strength. This in turn makes the smaller wheel stiffer. Since you're using the same materials, increased stiffness also increases transmission of vibrations -- as does the lower mass of the wheel, assuming the materials are of the same type. In this respect, "flex is flex" - it doesn't matter which direction the material moves, what matters is how efficiently the "wheel system" dampens vibrations.

Similarly, wheels with fewer spokes also tend to be harsher. The rims need to be stiffer, lacing patterns are different, there are fewer spokes to absorb shock, tension needs to be higher, and so forth.OK, let's just focus on one aspect. I do agree that bigger wheels must flex more. The problem I have with this argument is that the amount is insignificant. If you ride over a sharp bump, the pneumatic response of the tyre is such that at the first instant, the tyre deflects inwards before climbing over the bump. The amount it flexes is equal to the bump size. So let's say that the bump is 10mm. If you calculate/measure the amount of rim inwards deflection (see those wheel papers I linked to in another thread, forget the name) it is far less than 1mm, perhaps 0.2mm maximum (assuming the spokes are properly tensioned for the load). Now for a 406 wheel, that amount is proportionally smaller by 406/622, so about 2/3, about 0.13mm. So you are saying that you can feel the difference between 2 wheels due to that 0.06mm of difference between the 2 cases. That's less than the thickness of a sheet of paper!

You see why this is unbelievable? I am not the only skeptic about such magnitudes being felt. See here (http://sheldonbrown.com/gloss_ra-e.html#radial).

Is this definitively true?! Hadn't heard that before.When racers started using Moultons in racing, it was very clear that especially in pace lines followed by sprints, as many road races end, the F frame Moultons were all but unbeatable. In track racing they also showed a clear edge. This was attributed to the smaller wheels allowing closer drafting. Any advantage like that is extremely important in racing where even the smallest edge over the competition will make a difference.

I have to admit I don't recall where I read this, but it was in Moulton stuff, perhaps Tony Hadland's pages.

I did see an interview with Alex Moulton where he also mentioned same, and that they were banned from racing as a result.

Y'know makeinu, it is really sad to see you blatantly mischaracterize my position -- mostly because you are apparently so blinded by your own views that you're incapable of anything other than a black and white perspective.

I'm quite consistent in pointing out both the pros AND cons of folding bikes. It's almost as much coincidence as anything else that right now, I have no particular use for a folding bike. If I had a multi-mode commute or was going to fly with my bike twice a year, my choice of bikes would be different.

Fortunately, my comments stand for themselves, for those who can read them with equanimity.


So, on to rational discussions: ;)


I do agree that bigger wheels must flex more. The problem I have with this argument is that the amount is insignificant. If you ride over a sharp bump, the pneumatic response of the tyre is such that at the first instant, the tyre defelcts inward before climbing over the bump. The amount it flexes is equal to the bump size....
True, but the amount the tire can flex will also be affected by rim width, rim stiffness, tire width, tire pressure, tire surface area, load on the tire and so forth. When the tire compresses, it will spread outwards -- but only to its tolerance, at which point it has to transmit vibrations to the rest of the bike.

With a smaller diameter tire, impacts will be sharper, shorter, and more jarring. The tire may take most of the impact from a single small bump, but not necessarily all the impact from either a larger bump or an accumulation of waves generated by a rough surface.

Tires also don't flex all that much -- if they do, you're likely inviting a pinch flat or will knock the tire off the rim! The advantage to the pneumatic tire is that the alternatives, like solid rubber, have almost no give whatsoever.



So let's say that the bump is 10mm. If you calculate/measure the amount of rim inwards deflection (see those wheel papers I linked to in another thread, forget the name) it is far less than 1mm, perhaps 0.2mm maximum (assuming the spokes are properly tensioned for the load). Now for a 406 wheel, that amount is proportionally smaller by 406/622, so about 2/3, about 0.13mm. So you are saying that you can feel the difference between 2 wheels due to that 0.06mm.
I agree that few people, if any, are that sensitive.

However, we are not riding all day on a smooth track with a single, isolated and unique 10mm bump.

In the real world, you're constantly encountering variations in the road surface. In addition to the repetition, the waves interact, resulting in various changes in frequency and amplitude. The tires are also already partly compressed due to rider / frame / load weight; so the tire compresses further, attempts to return to its original state, hits another bump or dip; I presume these oscillations also produce waves of vibrations.

Need I mention that a tire isn't going to absorb 100% of the vibrations? (Does anyone know the percentage?) I really can't imagine that any tire, let alone any suspension system, is that effective. If it was, all you'd need is the right tire to make a Tata Nano ride like a BMW 5 Series sedan.

Separately, there are gaps or bumps that a 700c wheel can roll right over that 20" cannot, due to the difference in diameter. When dealing with a surface like cobblestones -- which, of course, still suck with larger wheels ;) -- you're going to have repeated rises and falls that are easier for the larger diameter wheels to roll right over, but will stick for 20" or smaller wheels. That, by the way, may be why I didn't see a single 20" wheeled bike except my own anywhere in Belgium. They are *cough* impractical in that environment.

Or, some might say, my environment. One of my daily rides involves stretches of smooth pavement, frequently broken up with train tracks, debris-strewn shoulders, cracked pavement, potholes, cobblestones, puddles, and tiled sidewalks. It's far from horrendous, but I'd say that's a bit more than just one single 10mm bump, yes? :D

Ergo, I would agree that if you compare a 36 double-butted steel spoke, aluminum rim, slick, 100psi 406 and 700c bike -- each with frames of roughly the same stiffness -- you are not going to notice the difference between a single 10mm bump.

However, that is a superbly artificial basis for comparison. In the real world, your tire cannot absorb all the impact of dirt, gravel, cobblestones, uneven pavement; in the real world, you're going to hit gaps and holes that 700c can roll right over but 20" cannot.

Unfortunately this seems to be a characteristic of your analyses: You appear to repeatedly isolate single facets, determine that the impact of that single facet is minute, and on that basis declare the totality of differences to be negligible. But there are numerous elements in play here -- including things we haven't even discussed, like shorter forks and smaller rear triangles -- that when combined, result in a significant difference for certain uses and scenarios.

So let's add a few things up, yes?
• Far less than 100% of vibrations can possibly be soaked up by any tire
• Smaller diameter wheel = more frequent vibrations, and bigger influence of smaller bumps and holes
• Smaller diameter tire can't compress as much as a larger tire
• Smaller diameter tire = less room for the tire to expand
• Stronger / stiffer rim means less ability for tire to expand
• Smaller rim also transmits more vibrations
• Shorter spokes = stiffer etc
• Less mass = more vibrations transmitted

In isolation one element may seem (or be) minute, but combined it adds up. Much in the same way that you can swap out one individual component and save an inconsequential gram here and there, but when you combine the result you've dropped several pounds off the bike. Right? :D


Last but not least.... If your theory is correct, it is still a mystery why designers like Moulton et al -- who have R&D resources and engineering staff -- choose to use mechanical suspension. Given the disadvantages of suspension (reduced performance, added weight, increased complexity, constant alterations in the rider's position relative to the frame etc.), why bother with if, if just lowering the PSI by 10% is sufficient to fix the problem? If you're right, isn't suspension superfluous?

To me, the answer is obvious: strictly reducing PSI, especially by a small percentage, is insufficient to smooth out the harsher ride of the smaller tires.

..............
However, we are not riding all day on a smooth track with a single, isolated and unique 10mm bump.................I think you missed the point. I was demonstrating with some real numbers the literally insignificant amount that wheels flex and absorb road irregularities. I'm picking on certain elements in the whole lot that you wrote because it is unfortunately riddled with inaccuracies (such as bottom bracket height) and in this case the myth that wheels flex. The point is they don't, so don't confuse the argument with stuff which is not true. My point is the effect is utterly dominated by tyre effects. Plus the rest of the bike flexes a whole lot more than the wheels - you will never ever feel the wheel effect. And now you want to further confuse the issue by introducing stuff like rim width. These parameters don't feature at all. End of that part of the discussion.

I'm an engineer so I am interested in repeatable stuff and real numbers, hence my calculation of wheel flex effects, and hence my calculation of tyre pressure effects. Real numbers count a lot more in my book than subjective experiences of whole bikes where you can't sensibly isolate wheel effects. It is not rigorous to blame wheel size which is a single parameter for a whole bike's ride quality. It's subjective. Let's stick to something which you can analyze properly.

The one example where a small wheel would suffer badly is in falling into a depression which closely hugs the wheel diameter. In such a case, the whole section of tyre that contacts the depression has to flex and due to the large increase in surface area, the amount of flex is reduced proportionally. Hence such a depression will be extremely harsh and be almost independent of tyre pressure. In such a depression a large wheel could roll over just contacting the edges.

However this argument can be turned on its head - the depression might match the size of the large wheel and it would now suffer the extreme jar, while the smaller wheel would roll down into it and up out the other side.

Another point is, your experience tells you certain things, which are different to my experience which tells me opposite things. Who's to say who's right? If you can demonstrate to me with some real numbers as I have, I'm willing to be convinced, but arguments like "you didn't see any 20" bike in such-and-such a place are subjective and quite irrelevant - there can be any number of explanations for the absence of 20" bikes.

So to re-cap, in order for me to take your argument seriously, I will need to see some numbers or other suitable rigor.

The reason you should take my argument, is I have a certain experience (opposite to yours), have puzzled why I don't experience my small-wheelers as worse than my big-wheelers, and come up with rigorous, testable explanations for my experience.

Perhaps your best angle would be to take a semi-random irregular road, and calculate/simulate the axle displacement on such a roads for various wheel sizes and tyre pressures and riding speeds. Perhaps the result will align with your experience.

I agree that few people, if any, are that sensitive.

However, we are not riding all day on a smooth track with a single, isolated and unique 10mm bump.

In the real world, you're constantly encountering variations in the road surface. In addition to the repetition, the waves interact, resulting in various changes in frequency and amplitude. The tires are also already partly compressed due to rider / frame / load weight; so the tire compresses further, attempts to return to its original state, hits another bump or dip; I presume these oscillations also produce waves of vibrations.

Need I mention that a tire isn't going to absorb 100% of the vibrations? (Does anyone know the percentage?) I really can't imagine that any tire, let alone any suspension system, is that effective. If it was, all you'd need is the right tire to make a Tata Nano ride like a BMW 5 Series sedan.

Separately, there are gaps or bumps that a 700c wheel can roll right over that 20" cannot, due to the difference in diameter. When dealing with a surface like cobblestones -- which, of course, still suck with larger wheels ;) -- you're going to have repeated rises and falls that are easier for the larger diameter wheels to roll right over, but will stick for 20" or smaller wheels. That, by the way, may be why I didn't see a single 20" wheeled bike except my own anywhere in Belgium. They are *cough* impractical in that environment.

Or, some might say, my environment. One of my daily rides involves stretches of smooth pavement, frequently broken up with train tracks, debris-strewn shoulders, cracked pavement, potholes, cobblestones, puddles, and tiled sidewalks. It's far from horrendous, but I'd say that's a bit more than just one single 10mm bump, yes? :D

Ergo, I would agree that if you compare a 36 double-butted steel spoke, aluminum rim, slick, 100psi 406 and 700c bike -- each with frames of roughly the same stiffness -- you are not going to notice the difference between a single 10mm bump.

However, that is a superbly artificial basis for comparison. In the real world, your tire cannot absorb all the impact of dirt, gravel, cobblestones, uneven pavement; in the real world, you're going to hit gaps and holes that 700c can roll right over but 20" cannot.

On the contrary, I think that although you may be able to imagine such situations, you will never encounter them in the real world due to the fact that traveling at speed effectively eliminates all the troughs of uneven surfaces. In the real world, you will never hit gaps and holes that 700c can roll right over but 20" cannot.

Also any engineer can tell you that the effect of a single bump can indeed be used to characterize the effect of larger bumps and accumulated waves of bumps. This can actually be calculated quite simply and perhaps Jur would be so kind to give us the fourier transforms of his simulation results.

Finally, concluding that no suspension could make a Tata Nano ride like a BMW 5 Series sedan has no bearing in the context of our discussion. Everything has a limit. Just because a 747 doesn't have enough power to get you to the moon that doesn't mean it can't take you around the world. It's perfectly reasonable to think that pneumatic tire suspension could be the end-all-be-all of suspensions for 200 pound loads while remaining woefully inadequate for multi-ton loads. Everything has a limit.



Unfortunately this seems to be a characteristic of your analyses: You appear to repeatedly isolate single facets, determine that the impact of that single facet is minute, and on that basis declare the totality of differences to be negligible. But there are numerous elements in play here -- including things we haven't even discussed, like shorter forks and smaller rear triangles -- that when combined, result in a significant difference for certain uses and scenarios.

So let's add a few things up, yes?
• Far less than 100% of vibrations can possibly be soaked up by any tire
• Smaller diameter wheel = more frequent vibrations, and bigger influence of smaller bumps and holes
• Smaller diameter tire can't compress as much as a larger tire
• Smaller diameter tire = less room for the tire to expand
• Stronger / stiffer rim means less ability for tire to expand
• Smaller rim also transmits more vibrations
• Shorter spokes = stiffer etc
• Less mass = more vibrations transmitted

In isolation one element may seem (or be) minute, but combined it adds up. Much in the same way that you can swap out one individual component and save an inconsequential gram here and there, but when you combine the result you've dropped several pounds off the bike. Right? :D

No, it's not the same because these factors aren't independent. Since they lessen each other the whole is not the sum of the already negligible parts, but far far less. Also, half the things on your list are just plain false because you're comparing 700c tires to much lighter smaller diameter tires, which isn't a fair comparison. Comparing tires of equal weight the first five items are all blatantly false.



Last but not least.... If your theory is correct, it is still a mystery why designers like Moulton et al -- who have R&D resources and engineering staff -- choose to use mechanical suspension. Given the disadvantages of suspension (reduced performance, added weight, increased complexity, constant alterations in the rider's position relative to the frame etc.), why bother with if, if just lowering the PSI by 10% is sufficient to fix the problem? If you're right, isn't suspension superfluous?

This is a good question especially because the Moulton Co was in the tire manufacturing business. However, I believe the answer is that on perfectly smooth surfaces a dedicated suspension can truely have zero losses because once it compresses it is effectively locked out, whereas a wide tire flexes similarly on both smooth and rough surfaces.

Either way both methods can be better implemented with smaller diameter wheels, which is a win/win because every bike uses one or the other (even bikes with large diameter wheels).

Also, your list of disadvantages is again, just false:
• On nonmirror surfaces suspension increases performance.
• Dedicated suspension on small wheels may not add weight compared to a large diameter pneumatic tires, but rather reduce it.
• It's arguable whether complexity is increased for a dedicated suspension. Making large dished wheels strong is fairly complex in itself.
• Dedicated suspensions between the wheel/frame interface (like on Moultons) doesn't change the rider position relative to the frame at all.



To me, the answer is obvious: strictly reducing PSI, especially by a small percentage, is insufficient to smooth out the harsher ride of the smaller tires.

I don't see how anything can be obvious when you can't get the majority of your facts right.

Small wheels = Harsh ride, Unstable handling, Low gearing.

Of course lighter wheels accelerates faster, but smaller wheels are not necessarily lighter. The lightest 20" wheelset I have seen is tyrell am7 wheelset which weighs around 1kg. And there are lots of 700c wheelset that weighs less than 1kg.

And moulton bikes used to be competitive at 1960's when all bikes are made with steel and weigh more than 10kg... Nowadays most parts of a road bike are made with featherweight carbon fiber (including wheels) and they are optimized in aerodynamics. However almost no small wheeled bikes care anything about weight, firring, stiffness, aerodynamics etc. So nowadays they just cannot compete.

I cannot understand why this discussion is going on anyway. Just ride a good modern 700c road bike that fits you for a while.

Also, your list of disadvantages is again, just false:
• On nonmirror surfaces suspension increases performance.
• Dedicated suspension on small wheels may not add weight compared to a large diameter pneumatic tires, but rather reduce it.
• It's arguable whether complexity is increased for a dedicated suspension. Making large dished wheels strong is fairly complex in itself.
• Dedicated suspensions between the wheel/frame interface (like on Moultons) doesn't change the rider position relative to the frame at all.


I have yet to seen a good, non-power-absorbing suspension. And I have definitely not seen any modern suspension on small wheeled bikes.
And dedicated suspension on small wheels add TONS of weight compared to vibration absorbing CF front/rear fork with larger wheels. (TSR fork alone weighs around 1.5kg, which is more than a frame AND fork of modern road bike)
Finally, why is making a large and strong wheel hard? Most bikes have them, don't they?

I think you missed the point. I was demonstrating with some real numbers the literally insignificant amount that wheels flex and absorb road irregularities....
I didn't miss the point. I fully accepted that you're not going to notice the difference when striking a single 10mm obstacle. I replied by pointing out that this is an artificial example that you never run into in the real world, and as such has limited utility. I'm also questioning several of the assumptions involved in your example.



My point is the effect is utterly dominated by tyre effects.
I noticed that, but again, that strikes me as incorrect - or at least unproven.

• Are you claiming that tires absorb 100% of the shock? 90%? 80%? What's the basis or evidence for your allocation of dampening to just the tire?
• What happens when the tire can no longer absorb shock? Obviously there must be a limit -- and bikes are constantly going over that limit, hence the feel of road buzz and of obstacles.
• Are you claiming that wheel mass has no effect on dampening? I.e. is it the case that if you have two objects of the same design and materials, and one has 25% less mass, that both will transmit the exact same amount of vibrations?
• Can you prove with an actual measuring device that a smaller tire, with the same PSI (or slightly lower), will absorb the exact same amount of impacts and vibrations as 700c?
• Why would reducing the size of a wheel increase its strength, but have no effect on its stiffness, when we use the same materials?
• Why doesn't a reduction in the size and volume of the tire change its compression and/or dampening properties? Isn't that one of the reasons why a skinnier tire is harsher?
• It's very clear that spoked wheels do flex. In comparison, tri-spoke or disc wheels will have almost no flex. The question is: How much? Does a smaller wheel have significantly less flex than a larger one? Or is it your position that tri-spoke wheels are absolutely equal to spoked wheels in terms of comfort, dampening and vibration transmission? Is that equally the case on a track, on asphalt, on gravel, on dirt?
• Does rider / frame / load weight have no effect on the compression properties of a tire?



Plus the rest of the bike flexes a whole lot more than the wheels - you will never ever feel the wheel effect.
a) The flex of the rest of the bike depends upon the construction of the frame. A touring bike frame will have much more flex than a track bike; you'll feel a lot more with a stiff racing frame than a flexy touring frame.
b) We started this particular line of discussion with the explicit intention of focusing just on wheels -- in fact, you requested we talk only about tires. Now you're discussing the rest? Please make up your mind. :D



I'm an engineer so I am interested in repeatable stuff and real numbers, hence my calculation of wheel flex effects, and hence my calculation of tyre pressure effects.
But as an engineer, you should know as well as anyone that mathematical models are only approximations and theories, and you have to rely on actual measurements over and above the models in order to establish veracity. In case it isn't obvious, when you design your your model you could unknowingly downplay or omit a dozen parameters that turn out to have individual or collective influences on the result. In fact, the only way you can properly establish that Property X has an influence, and how much influence it has, is by performing a series of real-world tests to isolate the effect of X.

I.e. your numbers are not "real" until we've objectively measured them.

Since it seems that neither of us have the appropriate tools to measure road shock, and since you requested that we do not consider subjective experiences, I'm not sure where that leaves the debate.

Or do you routinely go into mass production of a product without ever developing a prototype and doing actual product testing? :D



...the depression might match the size of the large wheel and it would now suffer the extreme jar, while the smaller wheel would roll down into it and up out the other side.
Except that the smaller wheel will have two impacts -- going into the hole and coming out. Or it would strike the exit at a more severe angle, depending on the shape of the depression.

Sorry, but it seems very clear that larger diameter wheels are smoother when encountering obstacles. Next....



The reason you should take my argument, is I have a certain experience (opposite to yours), have puzzled why I don't experience my small-wheelers as worse than my big-wheelers, and come up with rigorous, testable explanations for my experience.
Unfortunately, that process lacks veracity without objective tests. Obviously this affects any position on the debate and may well render any non-theoretical discussion moot.

As far as I can tell, none of us has done any real-world test using an objective measuring tools. I'm not sure anyone has; they certainly haven't published anything -- if they had, a) every 20" bike manufacturer would cite the evidence and b) we'd be discussing the specifics of those studies, rather than bandy our theories about.

I.e. at this point, your discussions are purely theoretical. The fact that numbers have specificity that gives the impression of precision does not make up for the fact that without an actual, repeatable, objective real-world test, you're dealing every bit as much with theory as anyone else here. Or, again, that your theories may accidentally omit or downplay factors that, contrary to common sense or expectations, turn out to be significant.

Or, to recap ;), in order for me to take your position seriously, you need to present actual physical evidence, using objective measuring tools.

Until then, I stand by my experiences; feel very confident in my assessment of the pros and cons of 20" bikes and 26" / 700c alike; the compromises required of folding bikes; recommend for them when appropriate and against them when they are not; and note the utility and enjoyment of 700c bikes for a wide variety of purposes when the fold is not required, advantageous or merely preferred.

Is this not the silliest thread ever? Hmmm...

Nah...I'd just call it pointless....;):lol:

Small wheels = Harsh ride, Unstable handling, Low gearing.

Of course lighter wheels accelerates faster, but smaller wheels are not necessarily lighter. The lightest 20" wheelset I have seen is tyrell am7 wheelset which weighs around 1kg. And there are lots of 700c wheelset that weighs less than 1kg.

And moulton bikes used to be competitive at 1960's when all bikes are made with steel and weigh more than 10kg... Nowadays most parts of a road bike are made with featherweight carbon fiber (including wheels) and they are optimized in aerodynamics. However almost no small wheeled bikes care anything about weight, firring, stiffness, aerodynamics etc. So nowadays they just cannot compete.

I cannot understand why this discussion is going on anyway. Just ride a good modern 700c road bike that fits you for a while.

I have yet to seen a good, non-power-absorbing suspension. And I have definitely not seen any modern suspension on small wheeled bikes.
And dedicated suspension on small wheels add TONS of weight compared to vibration absorbing CF front/rear fork with larger wheels. (TSR fork alone weighs around 1.5kg, which is more than a frame AND fork of modern road bike)
Finally, why is making a large and strong wheel hard? Most bikes have them, don't they?

The thing is, none of this has any bearing on whether or not large wheels are pointless and whether or not a particular design could always be improved with smaller wheels.

You will find unique parts and unique bicycles in many categories. Sometimes that is due to the advantage of the unique format and sometimes it's just coincidence and in the case of the large wheel format it is a coincidence driven by the conspicuous waste of those attracted to the pointless diversion of UCI cycling sport, which by it's very nature tries to squeeze the most out of inferior formats.

There's no question that all the parts and cycles you mentioned could be made better with smaller wheels if the right people had the inclination. The question is why would anyone have the inclination when such bicycles serve practically no useful purpose? They are pointless.

I didn't miss the point. I fully accepted that you're not going to notice the difference when striking a single 10mm obstacle. I replied by pointing out that this is an artificial example that you never run into in the real world, and as such has limited utility. I'm also questioning several of the assumptions involved in your example.



I noticed that, but again, that strikes me as incorrect - or at least unproven.

• Are you claiming that tires absorb 100% of the shock? 90%? 80%? What's the basis or evidence for your allocation of dampening to just the tire?
• What happens when the tire can no longer absorb shock? Obviously there must be a limit -- and bikes are constantly going over that limit, hence the feel of road buzz and of obstacles.
• Are you claiming that wheel mass has no effect on dampening? I.e. is it the case that if you have two objects of the same design and materials, and one has 25% less mass, that both will transmit the exact same amount of vibrations?
• Can you prove with an actual measuring device that a smaller tire, with the same PSI (or slightly lower), will absorb the exact same amount of impacts and vibrations as 700c?
• Why would reducing the size of a wheel increase its strength, but have no effect on its stiffness, when we use the same materials?
• Why doesn't a reduction in the size and volume of the tire change its compression and/or dampening properties? Isn't that one of the reasons why a skinnier tire is harsher?
• It's very clear that spoked wheels do flex. In comparison, tri-spoke or disc wheels will have almost no flex. The question is: How much? Does a smaller wheel have significantly less flex than a larger one? Or is it your position that tri-spoke wheels are absolutely equal to spoked wheels in terms of comfort, dampening and vibration transmission? Is that equally the case on a track, on asphalt, on gravel, on dirt?
• Does rider / frame / load weight have no effect on the compression properties of a tire?



a) The flex of the rest of the bike depends upon the construction of the frame. A touring bike frame will have much more flex than a track bike; you'll feel a lot more with a stiff racing frame than a flexy touring frame.
b) We started this particular line of discussion with the explicit intention of focusing just on wheels -- in fact, you requested we talk only about tires. Now you're discussing the rest? Please make up your mind. :D



But as an engineer, you should know as well as anyone that mathematical models are only approximations and theories, and you have to rely on actual measurements over and above the models in order to establish veracity. In case it isn't obvious, when you design your your model you could unknowingly downplay or omit a dozen parameters that turn out to have individual or collective influences on the result. In fact, the only way you can properly establish that Property X has an influence, and how much influence it has, is by performing a series of real-world tests to isolate the effect of X.

I.e. your numbers are not "real" until we've objectively measured them.

Since it seems that neither of us have the appropriate tools to measure road shock, and since you requested that we do not consider subjective experiences, I'm not sure where that leaves the debate.

Or do you routinely go into mass production of a product without ever developing a prototype and doing actual product testing? :D



Except that the smaller wheel will have two impacts -- going into the hole and coming out. Or it would strike the exit at a more severe angle, depending on the shape of the depression.

Sorry, but it seems very clear that larger diameter wheels are smoother when encountering obstacles. Next....



Unfortunately, that process lacks veracity without objective tests. Obviously this affects any position on the debate and may well render any non-theoretical discussion moot.

As far as I can tell, none of us has done any real-world test using an objective measuring tools. I'm not sure anyone has; they certainly haven't published anything -- if they had, a) every 20" bike manufacturer would cite the evidence and b) we'd be discussing the specifics of those studies, rather than bandy our theories about.

I.e. at this point, your discussions are purely theoretical. The fact that numbers have specificity that gives the impression of precision does not make up for the fact that without an actual, repeatable, objective real-world test, you're dealing every bit as much with theory as anyone else here. Or, again, that your theories may accidentally omit or downplay factors that, contrary to common sense or expectations, turn out to be significant.

Or, to recap ;), in order for me to take your position seriously, you need to present actual physical evidence, using objective measuring tools.

Until then, I stand by my experiences; feel very confident in my assessment of the pros and cons of 20" bikes and 26" / 700c alike; the compromises required of folding bikes; recommend for them when appropriate and against them when they are not; and note the utility and enjoyment of 700c bikes for a wide variety of purposes when the fold is not required, advantageous or merely preferred.

This is tedious. Do you need to personally walk each step around the earth to convince yourself it's round?

You can sit here all day questioning Newton if you like, but those of us that are engineers are perfectly willing to accept that small wheels are better as the laws of physics indicate.

The fact that you and the other naysayers of this thread have to resort to the most pointless applications in cycling in order to even begin to grab hold of a single advantage for large wheels is quite telling.

Folding bikes have compromises, but small wheels are not one of them. On the contrary, it is quite clear that going with a large wheeled format is a compromise needed to stick with the status quo and whatever social/economic benefits it provides.

On the contrary, it is quite clear that going with a large wheeled format is a compromise needed to stick with the status quo and whatever social/economic benefits it provides.

Hilarious. Almost as hilarious as your user name (a derogatory term for a 30+ single woman with no marriage prospects).

The thing is, none of this has any bearing on whether or not large wheels are pointless and whether or not a particular design could always be improved with smaller wheels.

You will find unique parts and unique bicycles in many categories. Sometimes that is due to the advantage of the unique format and sometimes it's just coincidence and in the case of the large wheel format it is a coincidence driven by the conspicuous waste of those attracted to the pointless diversion of UCI cycling sport, which by it's very nature tries to squeeze the most out of inferior formats.

There's no question that all the parts and cycles you mentioned could be made better with smaller wheels if the right people had the inclination. The question is why would anyone have the inclination when such bicycles serve practically no useful purpose? They are pointless.

It is plain wrong to blame UCI for everything. People are buying "ordinary' bicycles NOT because UCI are forcing them to. They are because they suit their needs better. 99.9% of the people don't know what UCI is anyway, and 99% of bikes are not built for any kind of competition.

One clear example is UCI 15lbs weight rule. A bicycle lighter than 15lbs is banned from UCI events, but nowadays EVERY bicycle company are making sub-15lbs stock bikes and people are willing to buy one if they afford to. People will buy good products (if available), and bicycle companies will produce bicycle that will sell.

In nutshell, if small wheeled bikes are indeed superior than large wheeled bikes, bicycle companies will make them and people will buy them regardless of what UCI says.

In eastern countries I live small wheeled bikes are quite popular and many club rides and races are held with such bikes. NO SINGLE PERSON argues that he is faster on a small wheeled bikes than a 700c road bike. That is the real world result without assuming unnatural things (mirror-smooth surface, perfect flat road, perfect pedaling etc)

Just tell me a single example of small wheeled bike that is comparable in performance with modern pro tour bikes. If there are no such bike so far, your first claim is pointless.

Is this not the silliest thread ever? Hmmm...

You can't tell me that a 20" wheel is just as comfortable to ride as a 27" of any width you choose.

Say a big pothole is coming up and its 2" deep and 6" from front to back and 6" wide. Roll a 20 in there (any width, make it 4" if you want) and roll a 27" in there. What one drops in faster, stays in longer goes deeper in most potholes and jars the body more?

And then a bump that goes up, say a 2X4, its 2" high, 4" long and goes like 6" from left to right. You ride over it, the 20 bumps up how fast, and falls off how fast, and the 27?

As the diameter increases the rubber on the road part approches a dead flat and the inperfections in the road are more and more absorbed and minimised. Theres something I'm missing.

Looks like those high wheeler guys and gals knew a thing or two then. Probably rode across ditches without noticing them.



Ps - I'm not disputing any of your points, but I suppose it's all a matter of where we draw the line of practicality against riding comfort. Personally, she who must be obeyed will allow me to keep a 16" in the house ready for action, whereas a high wheeler would likely be forbidden. Same on the bus, train or taxi.

It is plain wrong to blame UCI for everything. People are buying "ordinary' bicycles NOT because UCI are forcing them to. They are because they suit their needs better. 99.9% of the people don't know what UCI is anyway, and 99% of bikes are not built for any kind of competition.
I don't think is the situation. I think people buy whatever there is on the market. Big-wheelers are perceived as 'normal', while small-wheelers are perceived as 'toy'. Childrens bikes have small wheels. Adults bikes have big wheels. Ergo, 99% of people buy what they perceive to be what is proper for them. They don't know anything more than that. Only we know more because we are interested in smaller wheels.

I don't think anybody ever claimed small wheels are not harsher. I claimed that by judicious choice of tyre pressure and tyres, for practical purposes you can match a small wheel response with a big wheel. The very slightly higher rolling resistance of a small wheel is amply compensated for by aerodynamical advantages.

I don't think anybody ever claimed small wheels are faster. It is claimed you can draft closer and so expend less energy. Moultons were faster in their day but nobody suggested they would be faster today, they are too heavy. BUT if you built a small-wheeler of the same weight, you'd end up with the same advantage again as in those days.

Nobody claimed that small wheels are lighter. Sure you can buy roadie wheels that's lighter. But if those same materials and development effort went into small wheels, they would be even lighter than the lightest big wheel money can buy, and be stiffer to boot.

In eastern countries I live small wheeled bikes are quite popular and many club rides and races are held with such bikes. NO SINGLE PERSON argues that he is faster on a small wheeled bikes than a 700c road bike. That is the real world result without assuming unnatural things (mirror-smooth surface, perfect flat road, perfect pedaling etc)

Just tell me a single example of small wheeled bike that is comparable in performance with modern pro tour bikes. If there are no such bike so far, your first claim is pointless.

Single example? How about almost all world records:
http://www.ihpva.org/hpvarech.htm