69chevy

The latest trend in pro cycling is for the rider to “fit”themselves onto a smaller than “recommended” frame and compensate for the reduced reach by using stems much longer than any off the shelf bike comes with from the factory.

A typical response to this trend from forum members is “just because the pros are doing it, doesn’t mean we should”.
My first question was… why are the pros doing this?

At first glance, a couple of the benefits are obvious. The smaller frame weighs less, is stiffer and has a shorter head tube. Ok, so that explains a couple of reasons…

But those aren’t the only reasons why many are riding frames that are “too small”.

Think about the reasons a TT bike is “faster” than a roadbike…

On the surface you can easily tell a TT bike is more aero.The smaller frontal area of the rider is key in the extra speed.
But… there are also biomechanics that add to the speed that aren’t as apparent.

Picture trying to squat a heavy weight.

Standing (weight over your feet) is much easier than trying to squat from a seated position with the weight behind your feet. People’s legs naturally make more power when they are more vertical.

Getting your legs more vertical on a bike (because of the geometry) means one of two things. Either you have to sit more upright (bad for aero) or you have to shift weight distribution towards the front wheel (bad for handling and stability).

Riding a “too small” frame is a racers solution.

It gets the riders hips closer to being over the cranks (smaller frame means more upright seat tube angle) and wisely choosing the right seat post and stem length allows them to push the weight distribution as far forward as they are comfortable with.

Getting the reach right without putting too much weight forward is also countered with very low handle bars in relation to the seat, as this adds some of the reach back without moving weight more forward.

Of course, riding in this position is harder than the standard fit that recreational cyclists are used to, but I assure you it is a more powerful position.

I have been experimenting with different positions all summer.Partially because I want to go faster, but partially because I am interested in the biomechanics.

All this being said… there is no “right” that works for everyone, but in my experience, evolving my fit to closer match the positions of the fastest cyclists has played a significant part in my gains this year.

Spoonrobot 

not interested in faster, want to ride better.

PepeM

Is there any reference suggesting the 'pros ride smaller frames' claim is actually true? Smaller in relation to what? What's the percentage of riders in the peloton doing it? Has anyone asked them why?

Posting two or three pictures =/= proof by the way.

Dan333SP

It would be if he included this picture after 2 or 3 photos of smallish looking pro frames-

PepeM

Don't even care anymore, just read that Rapha is releasing a helmet.

69chevy

I don't have a full list to give you with percentages, so I'll give you a condensed version.


Wiggins is 6'3" 55cm bike
Froome is 6'1" 54cm bike
Sagan is 6'0" 56cm bike
Van Garderen is 6'1" 56cm bike


Traditionally, 6' tall means 58cm frame. The reason I was interested in these riders and their fit, is that they are 6 feet or taller. I am 6'3".

69chevy

So is better slower?

Dan333SP

To be fair to OP, pros do typically ride a size or two smaller than what the average roadie would be on for a given set of body dimensions, and run much longer stems (120-140mm is normal). I think it's less about centering legs over the BB and more about getting lower on the front end, as a smaller frame size will almost always have a lower head tube.

It's also been discussed here in years past-

https://www.bikeforums.net/profession...ong-stems.html

noodle soup

I definitely don't care about a Rapha helmet.

PepeM

Why not? Best way to match your helmet to your Rapha socks.

69chevy

I agree with lower, but look at saddle position here.


Also look at the stem.

Dan333SP

Can't wait for the promo vids. Artsy, black/white footage of hipsters going head-first over the bars after hitting a curb and then enjoying an espresso.

69chevy

I would almost bet, the saddle is 5.001 cm behind the BB to comply with these UCI rules.


"The peak of the saddle shall be a minimum of 5 cm to the rear of a vertical plane passing through the bottom bracket spindle."


"The length of the saddle shall be 24 cm minimum "

Clipped_in

I think weight distribution over the wheels is a big part of it in addition to the things the OP mentioned.

BTW, I'm no pro but I am 6'-3" and I like a smaller frame. I ride a 58 w/ 175VTT fitted with a setback seatpost (20mm) and 130mm stem. I've been riding this way for about the past 6 years and have no intention of changing.

Maelochs

Actually it is not about getting the hips over the BB because the seat is generally well behind the BB ... look at the pictures. Because the body is leaning forward, the pelvis is not vertical and the correspondence between lifting a weight while standing has nothing to do with the rotational motion of pedaling while fully bent over.

TT/tri bikes use different muscles. I know some tri riders do big distance, but I have never seen a TT much over 40 km. Also, I am not sure the half-degree or degree difference in seat-tube angle is making that big a difference is saddle setback---they could use a straight instead of a setback post and change that.

Pretty much, while your observation (smaller frames) might be accurate, all your hypotheses seem to be wrong.

Dan333SP seems to have won the thread.

noodle soup

Long torso/shorter legs?

Dan333SP

Do I win a Rapha helmet?

PepeM

Only if you can do the Rapha-flick.

69chevy

The seat is required to be behind the pedals per the UCI to prevent high speed faceplants that would happen when the rider touched the front brakes.


If moving weight over the pedals doesn't produce more power, then standing during sprints and climbs is pointless???

WhyFi

So the training is going well?

69chevy

My twice a week group rides are going great.


Broke 20mph for 30 miles with 1,000ft of climbing.


Wanted to hit 20mph on this loop before riding 1K miles and did.

gsa103

You're forgetting that pro cyclists are a self-selected population. The typical pro cyclist has very long limbs and a short torso. A conventional fitting process would put those riders on a small frame, due to the short torso length.

A pro fit is aggressive, but when you consider their actual morphology, their fit isn't actually that much more extreme that a young healthy Cat 3 racer.

Clipped_in

No, not really. I'm fairly evenly proportioned. 34.8" biking inseam.

69chevy

I agree with that statement, but will add the Cat 3 racers I know also ride small frames with saddles flirting with the 5cm rule.

Carbonfiberboy 

Pedaling is not necessarily about leg extension strength. Getting lower is certainly a help but there are many better ways to get low than buying a too-small frame. TT riders move the saddle forward in order to open the hip angle. They get away with this because their upper bodies are supported by their aero bars and because 40k is a short ride. Being able to use more muscles is a feature of the standard road position over the TT position.

My guess is that folks who ride frames which seem smaller than their height would suggest as appropriate have somewhat unusual body proportions, in particularly shorter torso, longer legs. This is very common with all riders. Bikes marketed to women frequently have shorter than usual top tubes to account for common female proportions. However the frames are not "smaller," just different geometry.