Can someone describe the "modern" road bike fit?

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dsveddy
Posts: 99
Joined: Tue Jan 17, 2023 8:56 pm

by dsveddy

Requiem84 wrote:
Thu Jun 20, 2024 9:23 am
So, summarizing this for myself is:

- Many 'modern' pro's tend to go to a relatively smaller sized frame and use longer stems
- There is tendency to move more forward, closer to a TT position -> is the goal being more aero, or is the goal to peddle more efficiently?
- Some riders are starting to experiment with shorter cranks - goal likely is to make the aero position a bit easier in respect of hip flex (?)

One point I didn't see mentioned yet and I'm curious about the views of you all: sadle height. My latest fitter put me really low on the bike. According to him this was one of the recent findings in fitting, as this allowed much more activation of the glutes which are the strongest muscles in our body. It did not feel that natural to me, so I moved my saddle height slightly up halfway to my initial position and his position. Bit of a compromise. If I look at pro's, I see some riders sitting quite high with a lot of leg extension in the peddle stroke (Van der Poel), whilst others seem to sit quite low (Campenaerts?).

What are the thoughts on this?
Generally I think most peoples' first instinct is to ride too high, I see lots of experienced cyclists riding around with rocking hips--although it sounds like your fitter has taken you a step lower than that even. It's a philosphy that seems to be gaining popularity, I've watched quite a few bike fit analysis videos where the idea of an extra-low saddle comes up, although I've never heard of the glute activation rationale before.
Obviously it's going to feel weird to drop your saddle a ton, the specific muscles recruited by the new position won't be as strong. Why not try to lower incrementally towards their mark and see how that works for you?

Most informative analysis on saddle height (and why pros are so varied) that I've seen is in the RCA Video "Worst Pro Cyclists Bike Fits (Expert Bike Fitter Explains)" [YouTube]X2O8cuzNMhc[/YouTube]

cheapvega
Posts: 465
Joined: Sun Oct 06, 2019 1:12 pm

by cheapvega

What's the benefit of dropping the BB vs just raising the other hard points relative to it? With sloped TTs being the norm I don't think standover height would be an issue. Flexibility around crank length is a big selling point these days.

I am wondering more if we're just due a rethink of the road bike handlebar in general. Maybe it's just UCI tyranny but I don't race so I don't really care about all that. We already know the TT position is the most aerodynamically efficient and I want to say the most comfortable. Why not just create road bike handlebars that mimick it on existing geometry, while providing a safe level and optionality around controls? There's also just the general cultural taboo around TT attachments on road bikes. Maybe I am missing something but there seems to be an obvious and easier fix we are overlooking.

by Weenie


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toxin
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by toxin

i like where you're going

TobinHatesYou
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Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

cheapvega wrote:
Thu Jun 20, 2024 4:53 pm
What's the benefit of dropping the BB vs just raising the other hard points relative to it? With sloped TTs being the norm I don't think standover height would be an issue. Flexibility around crank length is a big selling point these days.

It’s more aero and it gets your CoM lower. If I ride a bike with 90mm BB drop vs an otherwise identical bike with 70mm BB drop, my entire body will be 20mm lower than vs the rest of the peloton.

repoman
Posts: 31
Joined: Mon Jun 10, 2024 3:28 pm

by repoman

warthog101 wrote:
Thu Jun 20, 2024 1:40 pm
repoman wrote:
Thu Jun 20, 2024 12:44 pm
I wonder when we will see the first purpose built forward leaning seatpost with super short nose saddle?
Isn't there some stupid rule by the UCI that the saddle nose cannot be farther forward than the center of the BB?

The problem with setting a seat low and to the rear for me was it caused knee pain when putting down a good amount of power, which makes sense considering a closed knee angle under load is how you blow your knees out when squatting. There is an optimal position for the knee angle to produce power (think about where you're strongest in a squat) so I think it would make sense to match that angle to the optimal area of the pedal stroke.

It'd be interesting to see the power data from the cranks of riders now and from the past of more lower seats to see if people are 'mashing' more...mashing the pedals makes more sense to me than trying to spread the power out evenly on the pedal stroke.
The nose of the saddle is required to be at least 5cm behind the centre of the bb
Is there any reason given for that?

toxin
Posts: 903
Joined: Tue Apr 18, 2023 5:56 pm

by toxin

probably "preserving the image of the sport" or some crap like that

apr46
Posts: 346
Joined: Thu Aug 26, 2021 1:46 pm

by apr46

cheapvega wrote:
Thu Jun 20, 2024 4:53 pm
What's the benefit of dropping the BB vs just raising the other hard points relative to it? With sloped TTs being the norm I don't think standover height would be an issue. Flexibility around crank length is a big selling point these days.
The two reasons to lower the BB rather than raising the HT are aero and handling. Regarding aero, you lower the frontal area of the system. Aero is complicated, so it would be hard to guess how much you could save and honestly its probably not a lot at the larger sizes since I doubt you would go lower than 80mm of drop due to pedal issues, but its going to be something. The handling effect is more important. While one can try and model it, it **should** help counteract the effects of a longer wheelbase along with less trail.
cheapvega wrote:
Thu Jun 20, 2024 4:53 pm
I am wondering more if we're just due a rethink of the road bike handlebar in general. Maybe it's just UCI tyranny but I don't race so I don't really care about all that. We already know the TT position is the most aerodynamically efficient and I want to say the most comfortable. Why not just create road bike handlebars that mimick it on existing geometry, while providing a safe level and optionality around controls? There's also just the general cultural taboo around TT attachments on road bikes. Maybe I am missing something but there seems to be an obvious and easier fix we are overlooking.
This is what the TooT Ashaa RR bar is. Unless you want to get rid of the drops and propose some sort of bull horn arrangement; their design increases reach by 38mm, narrows grip width to 260mm, and adds 35mm or so of rise.

The reasons why this is probably not as good as making a longer bike is that you are shifting the rider forward. The more dramatic suggested shifts are probably for the larger riders which is why you want to move the front wheel out to compensate.

CarlosFerreiro
Posts: 439
Joined: Thu Jan 08, 2009 1:41 pm
Location: Shetland, Scotland

by CarlosFerreiro

repoman wrote:
Thu Jun 20, 2024 7:43 pm
Is there any reason given for that?
I think when it first came in as a rule it was in response to the Obree tuck position.
Is the "modern fit" playing with some of the same biomechanic ideas that he did?

warthog101
Posts: 970
Joined: Wed Sep 25, 2013 10:05 am

by warthog101

repoman wrote:
Thu Jun 20, 2024 7:43 pm
warthog101 wrote:
Thu Jun 20, 2024 1:40 pm
repoman wrote:
Thu Jun 20, 2024 12:44 pm
I wonder when we will see the first purpose built forward leaning seatpost with super short nose saddle?
Isn't there some stupid rule by the UCI that the saddle nose cannot be farther forward than the center of the BB?

The problem with setting a seat low and to the rear for me was it caused knee pain when putting down a good amount of power, which makes sense considering a closed knee angle under load is how you blow your knees out when squatting. There is an optimal position for the knee angle to produce power (think about where you're strongest in a squat) so I think it would make sense to match that angle to the optimal area of the pedal stroke.

It'd be interesting to see the power data from the cranks of riders now and from the past of more lower seats to see if people are 'mashing' more...mashing the pedals makes more sense to me than trying to spread the power out evenly on the pedal stroke.
The nose of the saddle is required to be at least 5cm behind the centre of the bb
Is there any reason given for that?
They dont seem to need a reason. :roll: Harris tweed jacket wearing, pipe smoking, d'heads that they are.
It is a particularly stupid rule given it applies to TTs also. Shortened saddle nose is necessary ime.

chris1234
Posts: 95
Joined: Sun Oct 25, 2020 7:50 pm

by chris1234

TobinHatesYou wrote:
Thu Jun 20, 2024 5:39 pm
cheapvega wrote:
Thu Jun 20, 2024 4:53 pm
What's the benefit of dropping the BB vs just raising the other hard points relative to it? With sloped TTs being the norm I don't think standover height would be an issue. Flexibility around crank length is a big selling point these days.

It’s more aero and it gets your CoM lower. If I ride a bike with 90mm BB drop vs an otherwise identical bike with 70mm BB drop, my entire body will be 20mm lower than vs the rest of the peloton.
Until everyone else in the peloton is doing it.

rudye9mr
Posts: 570
Joined: Wed May 01, 2019 12:01 pm

by rudye9mr

Went from 704W(PR 2022) to 778W (PR 2024)

170mm to 165mm (only 6months on shorter crank).

In my case, could mean anything but seems 165mm has not capped my max power.

I'm 59kg.

inertianinja
Posts: 296
Joined: Wed Jan 26, 2011 3:14 pm

by inertianinja

I generally am not a fan of this newer fit, because it seems (to me) to have resulted in bikes and components all being longer reach.
As someone with a shorter torso compared to legs, bikes with long reach + long reach bars + long reach hoods is not going well for me. I also prefer my 172.5mm cranks rather than shorter (on my peloton, for example).

However, one interesting thing about this modern fit is that it seems to indicate that saddle position in relation to the bottom bracket isn't as binary as i thought - i suppose this means it's possible to be more forward of the BB without causing knee problems, so long as the saddle height/reach are adjusted?

Nickldn
Posts: 2008
Joined: Mon Mar 25, 2019 12:35 am

by Nickldn

inertianinja wrote:
Sat Jun 22, 2024 10:20 pm
However, one interesting thing about this modern fit is that it seems to indicate that saddle position in relation to the bottom bracket isn't as binary as i thought - i suppose this means it's possible to be more forward of the BB without causing knee problems, so long as the saddle height/reach are adjusted?
Well this is a good question. I really did my knees no good at all moving my saddle forward. It may be because I didn't lower it sufficiently, but I also found the power phase of my pedal stroke reduced as I moved the saddle forward. So I gave up on the whole idea. My saddle has gone back again and I don't feel any worse for it.

TobinHatesYou
Posts: 13009
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

inertianinja wrote:
Sat Jun 22, 2024 10:20 pm
I generally am not a fan of this newer fit, because it seems (to me) to have resulted in bikes and components all being longer reach.
As someone with a shorter torso compared to legs, bikes with long reach + long reach bars + long reach hoods is not going well for me. I also prefer my 172.5mm cranks rather than shorter (on my peloton, for example).

However, one interesting thing about this modern fit is that it seems to indicate that saddle position in relation to the bottom bracket isn't as binary as i thought - i suppose this means it's possible to be more forward of the BB without causing knee problems, so long as the saddle height/reach are adjusted?

Race bikes have either stayed the same or gotten shorter over the years, not gotten longer. Look at the SuperSix Evo. Look at the death of Trek's H1 fit. I really wish people would stop crying about bikes being too long/low. People with upright fits can always use more spacers, positive rise stems and positive rise bars. People with aggressive fits cannot adapt a too-tall bike to their fit.

And yes, you've just realized that saddle position is merely the radius of a circle around the BB, of which there are technically infinite degrees.

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toxin
Posts: 903
Joined: Tue Apr 18, 2023 5:56 pm

by toxin

Long legs, short torso, very narrow shoulders, ape index 1 here. going from 175 to 170 cranks, getting a tt saddle and lowering my front end like 4 cm has vastly improved my riding experience. going to add some extra reach and put on some narrower bars when i find ones i like enough.

Though i am 22 with not a lot of weight above the chest and actively work on functional mobility and strength so not a great example of someone who might have problems with fit.

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