Folding Bikes - Foldies vs Roadies

I always know that roadies are faster than foldies and recently orgz a comparision ride. The fastest foldie I have, the Dahon Speed Pro vs 3 roadies. 9 of my Dahon Club riders (all SP and one MU P8) joined in as well. This was for a 4.5km sprint on a relatively flat road with some very slight descents & climbs.

2 of our strongest riders manage to keep up with the roadies at 35-40kmh. I max 51kmh on the slight down slope on Schwalbe Marathon tires (not as good as Stelvios for sprints expectedly). At the finishing point, #1 roadie (Ridley Carbon ridden by a young 23 yo guy) was 20 secs ahead of #1 SP. #2 position was another roadie with #2SP just at its heels. #3 roadie was in the middle of the pack.

So in this rough shootout test, roadies are indeed faster as expected. In another race over 160km (with the same rider), the difference is even greater - abt 10%. Would this be your experience as well?

http://lovethefold.blogspot.com/2008/08/roadie-vs-dahon-shoot-out.html

I always know that roadies are faster than foldies and recently orgz a comparision ride. The fastest foldie I have, the Dahon Speed Pro vs 3 roadies. 9 of my Dahon Club riders (all SP and one MU P8) joined in as well. This was for a 4.5km sprint on a relatively flat road with some very slight descents & climbs.

2 of our strongest riders manage to keep up with the roadies at 35-40kmh. I max 51kmh on the slight down slope on Schwalbe Marathon tires (not as good as Stelvios for sprints expectedly). At the finishing point, #1 roadie (Ridley Carbon ridden by a young 23 yo guy) was 20 secs ahead of #1 SP. #2 position was another roadie with #2SP just at its heels. #3 roadie was in the middle of the pack.

So in this rough shootout test, roadies are indeed faster as expected. In another race over 160km, the difference is even greater - abt 10%. Would this be your experience as well?

http://lovethefold.blogspot.com/2008/08/roadie-vs-dahon-shoot-out.html

OldOne, maybe next time convince the riders to switch steeds... for the sprint.. then you could average the results and draw additional conclusions..

+1

By having different riders riding different bikes, you are changing more than 1 thing so the conclusion is muddled.

Plus it is important that all drive trains are optimally cleaned, lubed and adjusted, so that they don't schew the results. It will be difficult to have a strong conclusion.

I wouldn't call it 10% though. I would call it 1 or 2%, as by my experience my Swift is about 5-10% faster than my R20, but indistinguishable from a roadie I had. This assumes that in both cases, ie roadie & folder, you can aero tuck down equally to eliminate wind resistance from the equation as much as possible.

Good points esp abt switching steeds. The aero riding position does make a lot of difference esp after 30kmh in my opinion.

If the test was able to have all the riders with the same ability then a correctly geared Moulton, Bike Friday or Swift should be very close to a full sized roadie.

If the test was able to have all the riders with the same ability then a correctly geared Moulton, Bike Friday or Swift should be very close to a full sized roadie.

Ah, but there's still a significant weight difference between the Moulton and a good roadie. Even the New Series Moulton is about 22 lbs, a good roadie nowadays is 16, 17 lbs. That may not be significant on the flats, but in the hills (which is hard to avoid around my area) it is a big disadvantage.

Ah, but there's still a significant weight difference between the Moulton and a good roadie. Even the New Series Moulton is about 22 lbs, a good roadie nowadays is 16, 17 lbs. That may not be significant on the flats, but in the hills (which is hard to avoid around my area) it is a big disadvantage.

I thought smaller wheels fare better on hills, am I misinformed?

I thought smaller wheels fare better on hills, am I misinformed?

If everything else is equal, I agree that smaller wheels are better for hills, as they spin up faster. I actually have a 17 lb 20" folder, and it's very good for climbing.

However, my earlier statement in this thread is that a heavier bike is a disadvantage on the hills.

I thought smaller wheels fare better on hills, am I misinformed?There is some misinformation out there about smaller wheels climbing better. Some howlers out there:


Small wheels climb better due to a smaller diameter that needs to be rotated.-I have NO idea what this is supposed to mean in physics terms.


Tests have shown that up to 16 mp/h, the small wheel is more efficient that a big wheel. Between 16 and 33 mp/h there is little difference. Over 33 mp/h the gyroscopic effect of the big wheel makes it more effective. Most folks do not go over 33 mp/h.-"Tests?" What "tests?" Show me the money.


Reducing the weight of rotating parts, especially wheels, is doubly useful, as you effectively have to lift them up twice! *awoooooo hoooooowl*

I thought smaller wheels fare better on hills, am I misinformed?

For whatever this is worth, my 20" wheels skip off the pavement on steep hills unless I stand to pedal. My 700c wheels don't.

OldOne, maybe next time convince the riders to switch steeds... for the sprint.. then you could average the results and draw additional conclusions..

+1 brilliant point! Then some truths would be revealed. Need similar conditions on the day too.

Ah, but there's still a significant weight difference between the Moulton and a good roadie. Even the New Series Moulton is about 22 lbs, a good roadie nowadays is 16, 17 lbs. That may not be significant on the flats, but in the hills (which is hard to avoid around my area) it is a big disadvantage.


Ok then, I wonder if you had a folder and a roadie at exactly the same weight, with 2 riders of exactly the same weight and ability if there would be any difference on the flats, climbing, descending and sprinting?

Ok then, I wonder if you had a folder and a roadie at exactly the same weight, with 2 riders of exactly the same weight and ability if there would be any difference on the flats, climbing, descending and sprinting?

I actually have this situation. My black Fuji Team Issue is a carbon fiber 17lb bike with full Dura Ace drivetrain. My Dahon XX Anniversary Helios is also right around 17 lbs.

They're both excellent bikes and fun to ride. I have not done "scientific" tests on them for performance difference, but here are my anecdotal and honest thought about their differences:

- Flats - Probably very little difference. Although, I feel that 700C wheels roll more efficiently at higher speeds due to the higher angular momentum. Also, the Dahon's top gearing was around 95 gear inches with its stock setup, so it was a little disadvantaged when the paceline is going faster than 25mph or so. But, that is easily remedied.

- Climbing - As I said earlier, I actually do believe that smaller wheels are better for climbing,due to the fact that it spins up faster. My Rolf wheelset on the Dahon weighs 995 grams (!), the Easton wheelset on the Fuji weighs 1550g. Factor in the angular momentum impact and one can certainly see how it is harder to spin up the big wheels.

- Descending - I definitely feel more stable on the 700C wheels than the 406's. Maybe it's just my poor riding skills, though ..

- Sprinting - The Fuji wins again, I'm afraid. The hinges at the handlebar and mid-frame take a significant toll on rigidity when stomping on the pedals and pulling on the 'bars. There's no way around it. On a one-piece full size frame, it's a very confident feeling when I stand and pull on the bars. On the Dahon, particularly the Helios design, I just cannot pull as hard.

I have been on a two year search for a "portable roadie" - a folder than can keep me in the hunt on my weekend rides with the group. However, I have abandoned that idea because I simply have not been able to find one. That's why I put the Dahon up for sale and it is on its way to a new home. Maybe the Moulton TSR will come close, but it will weigh 24lbs.

Don't mean to start any wars here, just noting my honest observations about the bikes.

I thought smaller wheels fare better on hills, am I misinformed?

That's a half-truth that comes from the assumption that smaller wheels will always be lighter, but due to lack of engineering or just plain economics smaller wheels rarely achieve this potential. For example, in theory smaller wheels should be able to use fewer spokes, but in practice they never seem to be built that way because standard spoke placement, thicknesses, angles, alloys, etc have all evolved to be optimal for larger wheels and, thus, need to be relatively overbuilt when shoehorned onto small wheel designs (killing any advantage). That's not to say that there aren't small wheeled bikes being built with low spoke counts, it's just that for a given strength it seems that smaller wheels need to use more spokes than they would if optimally designed components were available.

Since the economics of the situation dictates that no manufacturer will custom engineer anything sufficiently close to what is available off the shelf, you have to look to radically different designs to see the effect. For example, an inline speed skater can usually beat the pants off a roadie in sprints or going up hills and, although the mechanics of skating are not as well understood as cycling, due to their re-engineering, inline skate wheels probably exhibit all the purported advantages of smaller wheels.

That's one of the things I find so interesting about being an engineer (albeit not a mechanical one): To engineer a superior product one must engineer a trojan horse that can not only trump existing products, but also weave its way past the status quo. In my opinion, small wheel racing designs have thus far failed to achieve this goal (though I would contend that the 8" wheeled Carryme from Pacific Cycles will blow any other commuter bike out of the water in terms of getting up to speed or going up hills with the minimal amount of effort).





Small wheels climb better due to a smaller diameter that needs to be rotated.
-I have NO idea what this is supposed to mean in physics terms.

I'm pretty sure they're trying to refer to the rotational inertia, but you can file this under the "don't you have to pedal more?" myth about small wheels because once you account for the higher gearing (and subsequent wheel spinning) the inertia is the same.





Tests have shown that up to 16 mp/h, the small wheel is more efficient that a big wheel. Between 16 and 33 mp/h there is little difference. Over 33 mp/h the gyroscopic effect of the big wheel makes it more effective. Most folks do not go over 33 mp/h.
-"Tests?" What "tests?" Show me the money.

I agree, unless he's referring to the (very difficult to measure) energy expended steering the bike it's hard to see how the gyroscopic effect could come into play (which, by the way, Jobst Brandt has argued is negligible compared to the qualitatively similar affect of fork trail).





Reducing the weight of rotating parts, especially wheels, is doubly useful, as you effectively have to lift them up twice!
*awoooooo hoooooowl*

Well, don't you agree that, neglecting surface friction, it requires twice as much energy to roll a wheel than slide it? Granted, "lift" is a bit misleading as gravity doesn't pull any harder on a rotating mass than a stationary one, but going over a hill is a longer distance than tunneling through it.


Ok then, I wonder if you had a folder and a roadie at exactly the same weight, with 2 riders of exactly the same weight and ability if there would be any difference on the flats, climbing, descending and sprinting?

Even two different road bikes of different design, but equal weight, are not guaranteed to perform exactly the same. There are too many other variables. The biomechanics of cycling is more complicated than most like to admit.

I actually have this situation. My black Fuji Team Issue is a carbon fiber 17lb bike with full Dura Ace drivetrain. My Dahon XX Anniversary Helios is also right around 17 lbs.

They're both excellent bikes and fun to ride. I have not done "scientific" tests on them for performance difference, but here are my anecdotal and honest thought about their differences:

- Flats - Probably very little difference. Although, I feel that 700C wheels roll more efficiently at higher speeds due to the higher angular momentum. Also, the Dahon's top gearing was around 95 gear inches with its stock setup, so it was a little disadvantaged when the paceline is going faster than 25mph or so. But, that is easily remedied.

- Climbing - As I said earlier, I actually do believe that smaller wheels are better for climbing,due to the fact that it spins up faster. My Rolf wheelset on the Dahon weighs 995 grams (!), the Easton wheelset on the Fuji weighs 1550g. Factor in the angular momentum impact and one can certainly see how it is harder to spin up the big wheels.

- Descending - I definitely feel more stable on the 700C wheels than the 406's. Maybe it's just my poor riding skills, though ..

- Sprinting - The Fuji wins again, I'm afraid. The hinges at the handlebar and mid-frame take a significant toll on rigidity when stomping on the pedals and pulling on the 'bars. There's no way around it. On a one-piece full size frame, it's a very confident feeling when I stand and pull on the bars. On the Dahon, particularly the Helios design, I just cannot pull as hard.

I have been on a two year search for a "portable roadie" - a folder than can keep me in the hunt on my weekend rides with the group. However, I have abandoned that idea because I simply have not been able to find one. That's why I put the Dahon up for sale and it is on its way to a new home. Maybe the Moulton TSR will come close, but it will weigh 24lbs.

Don't mean to start any wars here, just noting my honest observations about the bikes.

Your observations are consistent with my beliefs about the physics of cycling and the state of small wheel technology.

That said, I personally would like to know more about the relationship between fork trail and contact patch shape when it comes to self-correcting steering at high speeds ("stability descending"). Since contact patch shape depends on wheel diameter and trail can be adjusted independently of wheel diameter and both influence "stability" what I'm curious about in particular is to what extent trail can be used to cancel the rounder contact patch of smaller diameter wheels. Is it like inertia where the higher gearing can exactly cancel the size difference in all circumstances or is it like the frequency of oscillation when hitting a bump which Jur showed can be mostly (though not exactly) canceled out with wider tires?

I personally think that at lower speeds the rounder contact patch of small diameter wheels is more "stable" because it gives you more leverage to hold the wheel steady when a bump or pothole tries to turn it (which is far more likely to cause a crash than endoing without the wheel turning). However, I suppose at higher speeds one wants the opposite effect where the longer contact patch gives the force of friction of the tire against the road more leverage against you so that the wheel holds itself steady despite the input of the rider. The question is, to what extent can one get the best of both worlds? The first low speed affect should be independent of trail, while the other is closely related to trail. Can adjustment of trail produce exactly the same affect as adjustment of contact patch shape? If not can trail be used to approximate a longer contact patch at all speeds? If not, can trail be used to approximate a longer contact patch at one or more target speeds?

I don't have much of an opinion on flats, hills, sprints, etc--but I haven't seen anyone mention road conditions. My experience is that larger-diameter wheels deal noticeably better with grooves and potholes, so I'll tend to take uneven asphalt a little faster and more confidently when I'm not riding my Swift.

I have been on a two year search for a "portable roadie" - a folder than can keep me in the hunt on my weekend rides with the group. However, I have abandoned that idea because I simply have not been able to find one. That's why I put the Dahon up for sale and it is on its way to a new home. Maybe the Moulton TSR will come close, but it will weigh 24lbs.

Don't mean to start any wars here, just noting my honest observations about the bikes.



SesameCrunch,

Have you considered a Bike Friday Pocket Rocket Pro? According to BF, with a Durace groupset and light pedals you can get it down to approx 18.75 lbs, (8.6kg), maybe lighter if you use a carbon Campag Record groupset, that's about 6 lbs lighter than the Moulton.

SesameCrunch,

Have you considered a Bike Friday Pocket Rocket Pro? According to BF, with a Durace groupset and light pedals you can get it down to approx 18.75 lbs, (8.6kg), maybe lighter if you use a carbon Campag Record groupset, that's about 6 lbs lighter than the Moulton.

Yeah, that would be pretty good. However, $4,500 for that configuration is an issue. Also, I've kinda given up on that search for the portable roadie. I keep having to ask myself "why not just ride the big bike?". Haven't come up with a good answer yet. Finally, I just committed to the Moulton, and will have to remain faithful for an acceptable amount of time :love:.

What makes for a roadie? What makes for a good candidate for a good roadie?

Sorry if these are stupid questions, I don't know.

It's a matter of POWER,

20" inches wheel is OK, depending how:

You will need more POWER to be able to SPIN enough to make the same distance as a big wheels bicycle.


Regards

What makes for a roadie?

A bike that fits your measurements properly, that is reasonably light, has drop bars and good quality tyres.


What makes for a good candidate for a good roadie?

Somebody who can ride a good bike properly.....I have raced on my cheaper bike against rich guys who have the best bikes, latest gear and huge egos and have soundly trounced them. I think if you are reasonably fit and used to hard exercise, have good stamina and lastly, enjoy pushing the limits, you're a good candidate. ;)

Sorry if these are stupid questions, I don't know.

Not stupid, hope this helps

It's a matter of POWER,

20" inches wheel is OK, depending how:

You will need more POWER to be able to SPIN enough to make the same distance as a big wheels bicycle.


Regards

Why?

I actually have this situation. My black Fuji Team Issue is a carbon fiber 17lb bike with full Dura Ace drivetrain. My Dahon XX Anniversary Helios is also right around 17 lbs.

They're both excellent bikes and fun to ride. I have not done "scientific" tests on them for performance difference, but here are my anecdotal and honest thought about their differences:

- Flats - Probably very little difference. Although, I feel that 700C wheels roll more efficiently at higher speeds due to the higher angular momentum. Also, the Dahon's top gearing was around 95 gear inches with its stock setup, so it was a little disadvantaged when the paceline is going faster than 25mph or so. But, that is easily remedied.

- Climbing - As I said earlier, I actually do believe that smaller wheels are better for climbing,due to the fact that it spins up faster. My Rolf wheelset on the Dahon weighs 995 grams (!), the Easton wheelset on the Fuji weighs 1550g. Factor in the angular momentum impact and one can certainly see how it is harder to spin up the big wheels.

- Descending - I definitely feel more stable on the 700C wheels than the 406's. Maybe it's just my poor riding skills, though ..

- Sprinting - The Fuji wins again, I'm afraid. The hinges at the handlebar and mid-frame take a significant toll on rigidity when stomping on the pedals and pulling on the 'bars. There's no way around it. On a one-piece full size frame, it's a very confident feeling when I stand and pull on the bars. On the Dahon, particularly the Helios design, I just cannot pull as hard.

I have been on a two year search for a "portable roadie" - a folder than can keep me in the hunt on my weekend rides with the group. However, I have abandoned that idea because I simply have not been able to find one. That's why I put the Dahon up for sale and it is on its way to a new home. Maybe the Moulton TSR will come close, but it will weigh 24lbs.

Don't mean to start any wars here, just noting my honest observations about the bikes.

In my limited experience, I would say that these are a spot on observations. I feel less confident on descents on my Birdy. On climbs, if I'm with a group of riders that are better than me (usually the case), I get dropped, even with my light wheels equipped with Stelvios. My bike weighs in at about 22 pounds. (Could still shed 400gm from the wheels, and another 400gms elsewhere, but it would still be heavier than a road bike.)

Of course, if you have a stiff frame and a light bike (e.g. the 2009 Pacific Reach), you are good to go. Next bike, SC?

Of course, if you have a stiff frame and a light bike (e.g. the 2009 Pacific Reach), you are good to go. Next bike, SC?

:lol::lol:

It would have been. Then EvilV's Moulton showed up...:o

Why?

It takes more than one revolution of a small wheel to travel the same distance as one revolution on a big wheel.

You can keep the pace of a big wheeler but you will need to pedal like hell!!.


Regards

It takes more than one revolution of a small wheel to travel the same distance as one revolution on a big wheel.

You can keep the pace of a big wheeler but you will need to pedal like hell!!.


Regards

http://deephousepage.com/smilies/jawdrop.gif!


Let the http://deephousepage.com/smilies/flamethrow.gif begin!






:popcorn

It takes more than one revolution of a small wheel to travel the same distance as one revolution on a big wheel.

You can keep the pace of a big wheeler but you will need to pedal like hell!!.


RegardsYou lose. Gearing is selected such that pedalling cadence is similar.

You lose. Gearing is selected such that pedalling cadence is similar.

+1

To match a big wheeler you simply increase the size of your front chainring/s, instead of 53/39 you use approx 60/50 for a 20" wheel.

It takes more than one revolution of a small wheel to travel the same distance as one revolution on a big wheel.

You can keep the pace of a big wheeler but you will need to pedal like hell!!.


Regards


Smaller folders use non-Euclidean geometry to optimise their forward speed (distance travelled/time). It is indeed true to say it takes more than one revolution of a small wheel to travel the same distance as one revolution of a big wheel .

For instance, if we look at:

(x-j)^2 + (y-k)^2 = r^2

we can clearly see how this works.


On the other hand, for a circle center with polar coordinates: (c, alpha) and radius a:

r2 - 2cr cos(theta - alpha) + c2 = a2


the answer is certainly not what we expect.


In the non-Euclidean world of folding bicycles, we need to use:

x(t) = r cos(t) + j y(t) = r sin(t) + k

and up the gearing a bit to compensate.


I hope this makes it clearer.

Dr. F. Snafu
Technical Officer
Hyde Park Folding Bicycle Society.

Smaller folders use non-Euclidean geometry to optimise their forward speed (distance travelled/time). It is indeed true to say it takes more than one revolution of a small wheel to travel the same distance as one revolution of a big wheel .

For instance, if we look at:

(x-j)^2 + (y-k)^2 = r^2

we can clearly see how this works.


On the other hand, for a circle with center with polar coordinates: (c, alpha) and radius a:

r2 - 2cr cos(theta - alpha) + c2 = a2


the answer is certainly not what we expect.


In the non-Euclidean world of folding bicycles, we need to use:

x(t) = r cos(t) + j y(t) = r sin(t) + k

and up the gearing a bit to compensate.


I hope this makes it clearer.

Dr. F. Snafu
Technical Officer
Hyde Park Folding Bicycle Society.


What the hell.....?......just put on a bigger chainring :p

Thanks for the good stuff guys. The only conclusion I can make so far is no one claims that the foldie is faster than the roadie. Some feel no diff, some thinks there is a slight diff that roadies are faster or at least perform better in some way or the other.

The answer is not as straight forward :(

Wonder what responses I will get if this got posted on the roadie forum? Maybe a lot of cynicism or even sneers!

Smaller folders use non-Euclidean geometry to optimise their forward speed (distance travelled/time). It is indeed true to say it takes more than one revolution of a small wheel to travel the same distance as one revolution of a big wheel .

For instance, if we look at:

(x-j)^2 + (y-k)^2 = r^2

we can clearly see how this works.


On the other hand, for a circle center with polar coordinates: (c, alpha) and radius a:

r2 - 2cr cos(theta - alpha) + c2 = a2


the answer is certainly not what we expect.


In the non-Euclidean world of folding bicycles, we need to use:

x(t) = r cos(t) + j y(t) = r sin(t) + k

and up the gearing a bit to compensate.


I hope this makes it clearer.

Dr. F. Snafu
Technical Officer
Hyde Park Folding Bicycle Society.

Oh dear! I'm not totally understanding this theorem. I just subscribe to the PYAO theory of going fast - Pedal Your Ass Off :giver:....

Will you be offering tutorial sessions after the bun-stuffing session at the Aug. 24 HPFS meet to help clarify?

Oh dear! I'm not totally understanding this theorem. I just subscribe to the PYAO theory of going fast - Pedal Your Ass Off :giver:....

Will you be offering tutorial sessions after the bun-stuffing session at the Aug. 24 HPFS meet to help clarify?

jiji!!!

Yes Pedal as hell!!!

You can put any equations you want, but there is NOT WAY to make a 20" wheel to perform the SAME as a 700c, you would need smaller gearing, bigger chainrings and more POWER, than a regular 700c.

Folders are just for FUN.

Regards

jiji!!!

Yes Pedal as hell!!!

You can put any equations you want, but there is NOT WAY to make a 20" wheel to perform the SAME as a 700c, you would need smaller gearing, bigger chainrings and more POWER, than a regular 700c.

Folders are just for FUN.

Regards

:lol:

If you think bigger wheels are so superior in terms of power then why don't you just ride one of these?:
http://tbn0.google.com/images?q=tbn:_6Ds5R0OZ6lo4M:http://upload.wikimedia.org/wikipedia/commons/e/e1/Ordinary_bicycle02.jpg
Also are road bikes good for anything other than fun?

I agree that even with equivalent gearing you won't "get" a 20" wheel to perform the same as a 700c wheel because you won't find anyone to manufacture a 20" wheel with the same care as a 700c wheel, but there are lots of sub 6" wheels that will easily outperform 700c wheels (and since road bikes are just for fun anyway you can actually use those 6" wheels on the smooth roads that roadies ride on). FACT: search the road forum and you will find lots of confessions from roadies who have been trounced by little girls on sub 6" inline skate wheels.

However, the thing I don't understand why everyone obsesses about wheel size when where folders actually lose is in the frame. I've never heard anyone say that a Montague or 700c Dahon is faster than a Swift or Bike Friday. If folders are slower it's because their folding frames aren't stiff enough, their geometries are compromised for a smaller fold, and their nonstandard parts do not benefit from the same level of fine tuning of the design and manufacturing processes; not because they have smaller wheels.

FACT: search the road forum and you will find lots of confessions from roadies who have been trounced by little girls on sub 6" inline skate wheels.


And that's was going UP HILL?



:D

Wheel size? Power?? Going fast???
http://i532.photobucket.com/albums/ee323/Tarmacblossom/202kW-1.jpg
AGROTON X720 DCR 202kW

http://i532.photobucket.com/albums/ee323/Tarmacblossom/JaguarXJS202kW.jpg
Jaguar XJS 202kW, 19"

Sorry, I know this it not knew to you all, its just that I only now learned to put pics on bikeforums - I could not resist ;-)

:lol:


I agree that even with equivalent gearing you won't "get" a 20" wheel to perform the same as a 700c wheel because you won't find anyone to manufacture a 20" wheel with the same care as a 700c wheel, but there are lots of sub 6" wheels that will easily outperform 700c wheels (and since road bikes are just for fun anyway you can actually use those 6" wheels on the smooth roads that roadies ride on). FACT: search the road forum and you will find lots of confessions from roadies who have been trounced by little girls on sub 6" inline skate wheels.

However, the thing I don't understand why everyone obsesses about wheel size when where folders actually lose is in the frame. I've never heard anyone say that a Montague or 700c Dahon is faster than a Swift or Bike Friday. If folders are slower it's because their folding frames aren't stiff enough, their geometries are compromised for a smaller fold, and their nonstandard parts do not benefit from the same level of fine tuning of the design and manufacturing processes; not because they have smaller wheels.

There are 20 inch wheels out there that perform the same as a 700c wheel. They are very common in the recumbent world.

Are you stating that ALL folder frames are not as stiff as comparable "full sized " and what do you base that on?

Also are you saying that all folders use non standard parts? I don't find that to be the case with any of my Bike Fridays.

I have noted a lot of general statements like this on this folder forum and that is sad because many who read these comments will go with the lasting impression that "All folders" are in a single catagory and thus inferior to their " Full Sized" bretheren.

Yes, just about everyone has seen this, but for those who haven't: http://www.alexmoulton.co.uk/frames.asp?id=questions.

The Moulton as well as the Birdy and Mezzo monocoque frames are stiffer than a road bike. But all 3 are heavier.

As the link above pointed out, the world speed record for a conventional bicycle is held by the Moulton, which has 20" wheels. Recumbent bicycles - also typically with 20" wheels - are, of course, much faster than upright bicycles.

You can put any equations you want...

Regards



Thank you:


substitute u = x^2, then it becomes an integral where a trig substitution u = sin works.


I'm sure you'll find this to your satisfaction.

Most kind.

And that's was going UP HILL?

I personally don't drop roadies on my skates, but a good inline speed skater will tell you that he's faster uphill than a bike because he doesn't have to carry all that extra weight (8 small wheels vs entire bike...shoes/boots are a wash). Downhill is the problem due to the lack of good ways to brake.


There are 20 inch wheels out there that perform the same as a 700c wheel. They are very common in the recumbent world.

If you can get them then more power to you, but is anything ever really optimized when it comes to recumbents? They have such a large aerodynamic advantage (of which 700c highracers surrender some) that I doubt anyone would be able to tell if there were a recumbent whose 20" wheels performed 100% as well as 700cs.


Are you stating that ALL folder frames are not as stiff as comparable "full sized " and what do you base that on?

As far as frame stiffness goes, it's hard to argue that using triangulation (like a diamond frame) could be anything but stiffer than the monotube construction used in the vast majority of folders. Moreover, for those folders which do have diamond frames the hinges could not, at best, possibly contribute anything but extra weight.

Show me a folding frame (inclusive of seatpost and stemriser) that's just as stiff as a diamond frame of the same weight and fit and I will renege, but I think that diamond frames are pretty optimal in this regard (making anything else inferior by definition).



Also are you saying that all folders use non standard parts? I don't find that to be the case with any of my Bike Fridays.

I have noted a lot of general statements like this on this folder forum and that is sad because many who read these comments will go with the lasting impression that "All folders" are in a single catagory and thus inferior to their " Full Sized" bretheren.


The parts are nonstandard in their usage. For example, the hub on a 20" wheel spins faster at the same speed than on a 700c wheel, the rim brakes have slightly less torque, and brake pads rub the rim at a faster speed. All of this means that parts which have evolved and been designed for 700c wheels will be slightly out of tune on a Bike Friday. For example, the perfect formula for a brake compound will probably be slightly different at different rub rates, so anything that's been perfected for 700c wheels it is likely to be slightly imperfect for 451 wheels.

All folders are quite obviously not in a single category, but it's a simple fact of optimization that additional constraints/features (such as folding) can only lead to inferiority (ie, the best possible riding bike will always be at least as good as the best possible riding folding bike because one is a subset of the other). If there is any optimality in the design of standard components at all then folders are surely losing the benefit (except for Moultons which aren't really folders and fall short anyway because they weigh much more than a comparable road bike) and if there isn't (and hub widths, spoke thicknesses, frame alloys, etc are just chosen because it's more efficient for the retail chain to stick with arbitrary historical standards) then folders also lose simply for being different (and thus more difficult to get serviced at retail, etc, etc). Don't get me wrong, overall I think folders are way better than nonfolders (which are almost useless for anything practical in today's world), but if you don't actually consider the benefit of the folding feature it's a lose lose situation.

I also loath the sentiment that folders are inferior, but I don't think that saying folders are exactly the same as nonfolders helps because I don't think they are the same. Applying notions of size from regular bikes a lot of people expect folders to be lighter, but they are often heavier (and there is a reason why). I believe that this kind of misunderstanding discourages people from folders too and I think the best way to combat it is to try to understand the pros and cons that make folders what they are.


Yes, just about everyone has seen this, but for those who haven't: http://www.alexmoulton.co.uk/frames.asp?id=questions.

The Moulton as well as the Birdy and Mezzo monocoque frames are stiffer than a road bike. But all 3 are heavier.

Weight was implicit in my comment about stiffness. You can make a stiff frame out of rubber if you use enough of it, but rubber is not a stiff material. Monotubes are not a design choice that contribute to stiffness, but if you make them heavy enough then, sure, they'll be as stiff as you like.

As the link above pointed out, the world speed record for a conventional bicycle is held by the Moulton, which has 20" wheels. Recumbent bicycles - also typically with 20" wheels - are, of course, much faster than upright bicycles.

jiji

But the moulton they speak about is not the SAME CONVENTIONAL MOULTON :D

http://www.greenbicycle.com/moulton-why.htm

Regards

Not to dampen the enthusiasm around here, but that bike may have started life as a Moulton.....


http://www.greenbicycle.com/images/moulton/bike-speedrecord.jpg

but that isn't an "off the shelf" folder. That's a purpose built HPV designed to do one thing - go fast in a straight line on a closed course.

And unless another organization keeps different "records" for these event, his speed of 51 mph isn't even close to the current record of 81 mph (130.6 kph). They don't appear to have a "conventional riding position class", it winner take all.

http://www.ihpva.org/hpva/hpvarec3.html#nom32

thans dbill, good point!



But about the small wheels again...

Originally Posted by mjw http://www.bikeforums.net/images/buttons/viewpost.gif (http://www.bikeforums.net/showthread.php?p=7238154#post7238154) There's a video somewhere where there's a race between a Strida and A-bike and the one who rides the A-bike can barely roll.




http://www.youtube.com/watch?v=kVVgsQt1DK4


jiji it is funny STRIDA vs A-Bike 2

Regards

But the moulton they speak about is not the SAME CONVENTIONAL MOULTON :D

http://www.greenbicycle.com/moulton-why.htm

Regards

So what? The point is that it had 20" wheels.

So what? The point is that it had 20" wheels.+1

From a purely geometrical perspective and infinitely hard pumped tyres, small wheels will have more rolling resistance than big ones. But for real world cases ie finite tyre pressure, the difference becomes almost insignificant in the overall scheme of things.

Moultons actually have less rolling resistance than large wheels due to the suspension, I understand. I suppose that places Birdys in the same category.

Thanks for the good stuff guys. The only conclusion I can make so far is no one claims that the foldie is faster than the roadie. Some feel no diff, some thinks there is a slight diff that roadies are faster or at least perform better in some way or the other.

The answer is not as straight forward :(

Wonder what responses I will get if this got posted on the roadie forum? Maybe a lot of cynicism or even sneers!

I owned a fast 700c wheel 27speed and a 6-speed Brompton. My GPS would measure me along the flat averaging 18mph on my 700c and 16mph on my Brompton. The upper riding position of my drophandlebar 700c is almost identical to my S-bar Brompton. The difference in speed I account to:
- closer gears on the flat, have 3 gears where by Brompton has 2.
- able to drop on downhills and headwinds
- possibly lower rolling resistance.

As a % the folder is 11% slower.

I am looking for a 24" folder with drop handlebars and hope then my folder speed nudges up, although quick-release wheels and a bike bag may be the totally different way to get a compact large-wheel "folder".

I suppose the question you should ask on the roadie forum "what's the smallest suitcase you can pack your bike in?"

I owned a fast 700c wheel 27speed and a 6-speed Brompton. My GPS would measure me along the flat averaging 18mph on my 700c and 16mph on my Brompton. The upper riding position of my drophandlebar 700c is almost identical to my S-bar Brompton. The difference in speed I account to:
- closer gears on the flat, have 3 gears where by Brompton has 2.
- able to drop on downhills and headwinds
- possibly lower rolling resistance.

As a % the folder is 11% slower.

I am looking for a 24" folder with drop handlebars and hope then my folder speed nudges up, although quick-release wheels and a bike bag may be the totally different way to get a compact large-wheel "folder".

That seems to be my experience too. Thks for sharing...

That seems to be my experience too. Thks for sharing...

If was trying to get to a location as quick as possible, I'd use my big non-folder. For example, if I wanted to get from my home in Lancashire to get some fish & chips in Ambleside Cumbria and back home, round-trip about 120 miles, I could cope on my non-folder but right on my physical limits on my Brompton. However, if I were just to want to ride for 8 hours and pick a random direction for 4 hours, I'd use my Brompton because I wanted to allow for a change of plans and use public transport. If I wanted to spend a weekend away, and go into Keswick, Cumbria, then I'd use a Brompton and use B&B or a small tent and I'd ride 75 miles each way, and that would be quite easy and my folder just a black bag when stood asking for a room in the B&B.

Back from a 80 ride on my Brompton.