pinholecam

I have good bikes for both 700c and 406, and I do ride a fair bit (in fact, 380-400km/week for the past 3 weeks on these mix of bikes since I signed up for some silly 2017km challenge )
Raleigh MV8 (good wheels; Sora 53T/11-30T; Road bar setup)
Moulton TSR (good wheels; XT 55/11-36T; Road bar setup)
Tyrell IVE (good wheels, Saint 55/11-36T; flatbar setup - but when I lean down all the way for speed, its probably the lowest position of all my bikes)
The Tribike always carries x2 750ml bidons compared to only x1 for the Raleigh and Moulton, so its 750gm more if that matters.


My small bikes all give guys on more expensive mini velos a run for their money.
"Ideally" though, I would love a BF Pocket Rocket PRO with Dura Ace, 6-7kg.... maybe I'll get to that someday.


There is at least 3kph ave speed difference between the RB and the 3 small bikes.


To get the 'same' is not possible.
Too many differences to nit-pick on.
Frame is diff, wheel size diff, Aero characteristics, rider position, groupset diff
Eg. Is a Tyrell AM7 hub the equivalent to a Campagnolo Zonda? (there's just no measurement to such things)

So IMO, we will never get to 'same'.
I'm satisfied that with the same rider (ie. me), the speed is different.
However, at the end of a 200km brevet, after the beer and dinner, I just fold my Tyrell IVE and take a train home, while my friends discuss over sharing taxi or riding back.

Same thing with travel.
I just fold my bike and load up a coach (while friends on road bikes have to find out in advance if their bikes can be accepted; take off various parts to load up)
On flights, my foldie just goes into a box and on standard airfare, while my friends deal with booking a van to transport the bike in an even larger bike box, the fear of 'oversize' charges, and dismantling.

Rick Imby

What a difference wheels and tires can make. I recently added a set of Rolf wheels and mounted Durano 20 x 1.10 tires and I mounted them Tubeless for less rolling resistance.

I rode the same route that I did last fall when I started this thread. I was in better shape then. However today I was 1:50 faster at 15:19 when my best time on my 700c bike was 17.10.

I now need a bigger gear on my Dahon. I was spun out probably 20% of the time, not just downhill like i was with the fatter tires and original wheels.

Rick Imby

Your experience sounds interesting. Let me get this straight---some abbreviations I'm not sure about.

So you are saying your Road bike---700c carbon is about 2mph or 3kph faster?
Your Tribike has the forward extended hand position? Or is it standard Road bike bars?

Would one of your 406 bikes be significantly faster than the others?

pinholecam

Tri-bike is titanium and old, certainly over 10kg and not the <7kg bikes out there nowadays.
Its got aero-bars as its a Tri-bike, but either way on the aero bars or on the handlebars, its certainly faster.

Just looked at my Strava rides over this week, with the one on the Tri bike being the ones later in the week (so presumably more fatigued).
On the regular straight stretch that I ride on, I cruise (ie. easy breathing) at ave 35-37kph on the tri bike and 30-32kph on the mini velos (ie. Raleigh MV8 and Moulton TSR).


I would say that the Raleigh is a bit faster of my bikes.
Lighter (no fold), really stiff and basically a road bike geometry sized down.
I can imagine it being able to match any high end mini velo if I changed out the fork to a carbon one and got better 451 wheels like the Tyrell AM9. (but its my commute and I like to leave it cheaper in case of theft)

Rick Imby

Thanks for the info Pin Hole...

pinholecam

Funny, I end up quoting myself


Bike_Friday_PRSP_1 by jenkwang, on Flickr

I'll probably write on how it rides/handles once I've put in some distance on it.

jur

Ooohhh looking forward to it!

Nachoman

My road bike and my folder are both custom made, to almost the same specifications.
I don't know if I'm slower on my folder because of wheel size, gearing, less stability or what . . . but I've always chalked it up to weight, because my folder is about five pounds heavier.

Sangetsu

I've been off my road bike for nearly 2 years, riding my folder almost exclusively. As I have said in the past, these bikes weigh the same, and are set up to have the same cockpit size. The road bike is Campy Record 9 speed equipped, the folder, a Birdy with 20" wheels (Ultegra 6800 hubs), is Dura-Ace/XTR 11 speeds.

On Saturday I cleaned up my road bike, trued the wheels, made a few adjustments, and took it for a ride over the same closed course I have used for the last 4 weeks on my folder. My road bike was 10% faster per lap.

jur

If you have the ability, it may be instructive to lock the Birdy's suspension to see if that makes a difference. But besides that, I know the Birdy frame is very flexy indeed, that would soak up a fair bit of power too, and that is in the lateral plane which is exactly where you want maximum stiffness.

reppans

I'm now down to half my previous difference, or ~0.5mph/3.5% at the same air pressures due to the new drop aero position on Brompton. It's actually a bit more aerodynamic then the drop bars on my gravel bike (hands are together) and it's made big comfort difference by providing another back angle/hand grip position. Very happy with that.

pinholecam

Update to this thread..
Its been a while and I made some changes to my bikes, so here is the first one.

The Raleigh is now a 451 bike from the 406 before.

Raleigh MV9 sp by jenkwang, on Flickr

Its really interesting how much difference the 451 wheels make to a ride.
The bike feels even more "road bike like", maybe because it feels higher (higher center of gravity).
451 also seems to hold speeds better and roll over short climbs (eg 100m )easier most likely due to the holding of the momentum.
I have found this latter aspect to be rather stark between 700c wheels and 406 ones.
On 700c, on such short climbs, there is little effort needed as the bike basically rolls for at least half the climb, while on the 406, I'd have started to pedal 1/3 into the climb.
So in this respect, 451 certainly is a bit better than 406.


I'm not a measurement kind of guy, so I just take the bike out, run it over the past few months over the usual routes and group rides to see how the bike rides and my overall position in the usual peleton.

I have to say that the bike configured with 451 wheels (Tyrell AM9) is really close to a 700c bike.
In many group rides, its been able to not just keep up, but pull the group and often enough get within the top 3-4 finishers in the ride.
Base on what I later observe on my Strava, I'd still think that there is a 1kph to 1.5kph delta to my tri bike, but to be able to ride in a group of 700c bikes w/o feeling severely handicapped is great (esp on poor weather days when I'd not need to clean up the Raleigh after getting back from the ride at 11pm)

jur

This corresponds to what I experience also - the difference between my Ti Swift and a roadie is not really distinguishable beyond differences in feel due to handlebars, saddle, stretch and that sort of thing.

fietsbob

UCI says what shall be. .. don't forget the regulators.., so Nope.





...

pm124

My office banned bicycles inside the building for 10 years. During that time I owned a number of 20 inch bicycles. They were all folders of different brands and mix. For me, the Birdy was one of the fastest ones.

Then the school changed policy and allowed big bikes in the office. I bought a recumbent high racer. A very fast one. (Bacchetta). After that, I owned an even faster one. (M5 Carbon high racer.).

I rode these two bikes for about 10 years collectively. They both have 700 C wheels on these bikes even though I am getting older I am about 5 miles an hour faster on the M5 CHR than the Birdy.

Now in Thailand, I have a regular Trek Emonda Road bike, which I’ve been riding for three years. This bike is about 4 miles an hour slower than my recumbent on the flat. I still ride my recumbent when back in New York, and the speed difference is consistent.

I’m not sure that these data are worth anything, but I do know my power output and I do know my CDA. On the recumbent my FTP is about 180. On the Emonda It is about 210. The M5 CdA is .15 on the Trek it is probably about .3. Both have continental 5000 tires.

Power is lower on the recumbent because I am laying down and cannot recruit my glutes. But still about 4mph faster on that bike than my racing bike on the flats. On very steep hills, the Emonda is much faster. On rollers the recumbent is much faster.

Both bikes leave the Birdy in the dust. The Birdy has bullhorns and a reasonably aero position. The tires are slower Kojaks.

Apologies for the typos I’m dictating into my phone

MAK

I know that you asked about 20" wheels but the videos below compare Bromptons (16") vs. high end road bikes.


(Note...Two high end riders/the Brompton rider is Andrew Feather)
(Breaks down the above)

Jipe

I know these video's, they are not really convincing due to the way the comparison is made and also because there are 20" folding bikes much more efficient than the Brompton.

The Brompton has a lot of advantages but efficiency is definitely not its strongest point !

joey buzzard

Absolutely true. In an urban environment that sonsists of 200 meter sprints between traffic lights a 20" bike is pretty unbeatable due to its quick acceleration.

I also find my little bike climbs hills and mountain roads well.

It is however outclassed by 700c going downhill or long flat stretches as the larger diameter wheels carry momentum better and usually road bikes also just have more gear inches onboard (thanks again to their larger wheel diameter). I ride a Xootr Swift and find that I can tuck in and draft really fast roadies (even on aero bikes) over many flat Kms, but I cannot maintain being out in front at the highest speeds as the bike just isn't quite efficient enough to keep that up without someone breaking the wind.

​​​​​​20" wheels are also not ideal for rough or broken track. I ride it over such all the time because there's plenty of washed out dirt trails were I live and the bike does it alright, but larger wheels would be better and safer over uneven road surfaces.

Small wheelers are a lot of fun. They naturally accelerate quickly but over a certain speed more watts of energy are required to keep the wheels spinning. Considering their smaller storage profile I think that 20" is well worth considering if you want speed and the main ride environment is a city. And they're pretty good in many other environments too. All bikes are compromises.
​​

Fentuz

20" vs 700c is a little bit complex. As many mentioned, 20" folding bike are compromised as the main purpose is foldability which often leads to inadequate position. At best, the position is going to be like a flatbar hybrid.
Then, wheel size, it is difficult to size up there is a ~1.4 ratio (28" vs 20") so for example when racing hillclimbs, I run a 50T chain ring that give me similar GI as other competitors running 34T/36T on classic bike and on daily basis, I run a 56T chainring equivalent to 40T like many gravel bike.
Now compared to a regular amateur 700 with a compact crankset (50/34) or semi compact (52/36), I would need a 70/50 crankset with does not exist. (track racing with big rings tend to go up to 60 with 144 bcd).This is a bit of an issue downhill and on smooth flat. As Joey mentioned, the flywheel effect or lack off means that the rider has to be at higher cadence to keep up the speed.
The other big disadvantage is the aero, on downhill and flats Aero and rolling resistance are kings. A road bike is designed to minimise Wattage waste so there again the rider has to input more energy to keep up.

Uphill, different story, it is all about weight and range. A 20" minivelo with budget part will be as light as a mid range road bike ( my litepro aero wheels are the same weight as hunt carbon wheels) so they can climb faster hence racing my minivelo in hill chimbs rather than my carbon 700c. They accelerate faster too.

Boys/Girls racer to the traffic light type of thing, a good stiff 20" should be good because light, fast acceleration on short distance.


Basically you can compare it the sportscars:
- go on a big track like LeMans or Spa, you will be faster in a 911 GT3. In transposed cycling situation, roadbike has the advantage
-go on a small tight autocross/twistty hill climb, you will be faster in a caterham, In transposed cycling situation, 20" may the advantage
- go on a tight short track like Goodwood / Combe, you will OK with and elise/exige and should keep up with GT3s. In transposed cycling situation, 20" minivelo should work with roadbike pack but it will need a liitle bit more effort.

Jipe

Most 700 wheel size bike use a cassette with a smallest cog of 11t. The other solution to adjust the transmission to the smaller wheel size, instead of only increasing the size of the chainring, is to reduce the size of the smallest cog to 10t or even 9t.

Moving from 11t to 9t is equivalent to moving from 50t to 61t.

Companies making race small wheel bikes like Moulton use a 10t cog.

Fentuz

Yes, Tern did that with shimano capreo (9T cog). or go to XD/XDR with 11gears 10T for SRAM sunrace and 9 on e13. I run that on gravel/cyclocross so I can race with 32 or 36T chainrings

Jipe

The Riese & Müller Birdy Touring is factory equipped with a 10s 9-32t Sunrace cassette (that requires a specific Sunrace rear hub).

I upgraded my two Birdy with and XDR rear hub and a 9-32t 3T/e13 cassette on one and a e13 9-34 cassette on the other one (with a Shimano Ultegra RD-R8000GS rear derailleur).

Moulton use a proprietary rear hub and proprietary cassettes with a 10t smallest cog, both the hub and cassettes are derived from Campagnolo hub freewheel and cassettes.

pinholecam

Exactly my experiences riding with 18", 406 and 451 wheels.

The advantage of smaller wheels in traffic is that I find that I am more nimble to navigate thru traffic as well as being in an easier gear to 'get to' the dismounting point (ie. 12 and 6 o-clock positions ) which can happen often and suddenly in city traffic and lights.

Overall, I use a small wheeled bike for commute and after office rides. It does the job well enough and thats all I need to bother about during the weekday.

jfouellette

The comparison is interesting but is it really pertinent if you consider the actual use scenarios? Everything being equal, of course a larger wheel will be faster then a smaller one. Are you a speed demon? Get large wheels and chain rings and leg muscles 💪.

50PlusCycling

Noticeably. I’ve seen 20” bikes pass road bikes, and I have passed them myself on my Moulton. But not everyone who rides a road bike is fast or fit rider. Fitness being equal, a road bike will be faster.

I have an assortment of bikes, including folders, a mountain bike, and a road bike. My Birdy folder weighs less than my road bike, it is fitted with a Di2 driveline, 20” wheels, Schwalbe One tires, and the cockpit is set up the same as my road bike, meaning that my riding position is the same. Yet, I have never been able to match the same speed or time as my road bike over the same course.

Mountain bikes have moved away from 26” wheels to 27.5” and 29” sizes. You can argue that larger wheels offer an advantage over rough terrain, the deflection angle changes as wheel diameter increases, making it easier to go over obstacles and lose less speed. In regard to road bikes, roads are not perfectly smooth, and a better deflection angle will smooth out irregularities on road surfaces with less energy loss.

Another consideration is lateral movement, a smaller wheel has less gyroscopic effect than a larger wheel, meaning that there is more side-to-side motion when riding. A wiggly line is longer than a straight line, and therefore takes longer to follow.

All this said, I do most of my riding on my folding bike.