I know long ago some bikes were built to run a 650/700 setup but now we’re away from rim constraints has anyone tried straight up swapping in a 650c into the front lately?
Just interested if anyone has done any aero testing for sh*ts and giggles - it would allow a more aggressive body position, possibly reduce frontal area, and given that we’ve all moved to 130mm cranks I don’t think pedal strike is a worry…
I know long ago some bikes were built to run a 650/700 setup but now we’re away from rim constraints has anyone tried straight up swapping in a 650c into the front lately?
Just interested if anyone has done any aero testing for sh*ts and giggles - it would allow a more aggressive body position, possibly reduce frontal area, and given that we’ve all moved to 130mm cranks I don’t think pedal strike is a worry…
On a modern tri bike with disc brakes, possibly, you’d have more luck trying with a 650b instead: the size difference is minimal (584mm vs 571mm), and you’ll find plenty of modern features availability (disc brake, carbon rim, tubeless tires…); with 650c it’s a challenge even finding a 23mm wide clincher
They do under UCI and ITU rules
̶T̶h̶e̶y̶ ̶d̶o̶ ̶n̶o̶t̶ ̶u̶n̶d̶e̶r̶ ̶U̶S̶A̶T̶ ̶r̶u̶l̶e̶s̶
I stand corrected, it must have changed in 2023
a.) In general, UCI rules, as of January 1st of the current year, will apply during competition and
also during familiarization sessions and official training:
(i) CI road race rules for draft-legal triathlon and duathlon competitions;
(ii) UCI time trial rules for non-draft legal triathlon and duathlon competitions;
(iii) UCI Mountain Bike (MTB) rules for winter triathlon, cross triathlon and cross duathlon
competitions. World Triathlon Competition Rules 28 January 2022
b.) The bicycle is a human powered vehicle with two wheels of equal diameter. The front wheel
shall be steerable; the rear wheel shall be driven through a system consisting of pedals and
a chain. Bicycles are referred to as bikes and will have the following characteristics in the
following sections:
page 18
You can buy Gatorskins for training tires from many places.
I have such a big stock of tires I could race for the next 10 years. Personally I have at least four sets of 23mm Bontrager Aero TT’s and three 25mm Aero TT’s
I only wish somebody would make a bike that actually fits me. If anyone knows of a stock bike that you can get the pad stack down under 500, please let me know.
You can buy Gatorskins for training tires from many places.
I have such a big stock of tires I could race for the next 10 years. Personally I have at least four sets of 23mm Bontrager Aero TT’s and three 25mm Aero TT’s
I only wish somebody would make a bike that actually fits me. If anyone knows of a stock bike that you can get the pad stack down under 500, please let me know.
Preferably without a huge amount of pedal overlap.
Remind me: Aero TTs have the rubber lip around the rim interface?
Yes, those little wings that fit next to the rim so well and they were fairly thin and flexible.
I’ll take the toe overlap, I have in on every bike I own right now.
The best fitting 700C bike I have is my track bike. It has a low stack (480mm) because the bottom bracket is an inch higher than most other bikes.
Any manufacturer can do that with their smaller bikes, I don’t know why they don’t. An example is the Trek Superfly. There is no need to get the bottom bracket as low as others, the people riding that size are frickin’ tiny. Instead they just got rid of the bikes that fit and said F to 15% of the people that needed it.
Sorry, rant over. (You’ll probably hear it again out of me)
In fact, those are cheap training tires, unless you have a different definition for a $25 67TPI clincher.
I have a couple of old steel 650c bikes and run some of those Schwalbe’s on a few wheels: they’re not bad at all, but not a racing tire by any means, at least for my standards
This nixes my idle speculation (as well as scuppering my aero-penny-farthing idea). Thanks.
Interestingly it also states that power shall be transmitted by a chain. Is this new?? If not, it raises a question of why CeramicSpeed bothered with their complicated drive system a couple years back.
While I have not done this, I’ve read that you can turn the fork around backwards and the front end geometry will be very close to correct.
The other issue would be pedal clearance.
Yeah, no.
On forks with any significant offset at all, you’d go from a reasonable trail figure to one akin to using a caster where the axle trails the head tube axis. You sometimes see this done on track bikes used in derny races to allow the rider to get as close as possible to the derny. The increase in the trail value isn’t a problem on the track as you’re never really turning the wheel to make it 'round the banking. Plus, the typical track fork has very little offset, so turning it around doesn’t put it as far behind the steerer axis as a road fork turned around would.