[Ventruck]

I've taken note that the "climbers" in the Pro ranks similar to my height (but far superior to my performance) are running 120mm+ stems, notably Contador, Rasmussen and Pellizotti. Notably, I noticed Contador kept the same stem length when he moved from a 56cm Madone to a 52cm S-Works SL3.

Using logical thinking, this must largely have to do specifically with how far over the front wheel he wants to be. That then has me questioning, would he, as well as other climbers prefer stems at this end of the length "spectrum" for more weight over the front for well...better climbing?

So I'm curious to getting some insight about this. I've heard mixed takes on where weight should ideally be for climbing. Some say rearward for more weight on the pedals, and some say forward for the exact opposite reason. Does this choice in length even have anything do with weight placement? Or does it have to do with something else likie leverage, etc?

 

[Salsa_Lover]

you have to find a good compromise

for climbing seated, you'd want more seatback, for off the saddle climbing you'd want a long stem.

if you go with an smaller frame that what you would normally use, then it would weight less and allow you to have maybe a 32mm seatback seatpost and a long 120 or 130mm stem. the saddle to handlebars drop would be quite high.

It won't be a comfortable bike for centuries though.

 

[wim]

I've taken note that the "climbers" in the Pro ranks similar to my height (but far superior to my performance) are running 120mm+ stems, notably Contador, Rasmussen and Pellizotti. Notably, I noticed Contador kept the same stem length when he moved from a 56cm Madone to a 52cm S-Works SL3.

While you're singling out climbers, many pros are riding 120 mm + stems because they fit themselves on the smallest possible frame. It's also possible (but I'm too lazy to confirm this) that the horizontal dimensions of a 56 cm Madone and a 52 cm S-Works are much closer to one another as their nominal frame sizes would suggest. Point being, the connection between stem length and climbing prowess may prove to be nonexistent.

Interesting thought, nevertheless.

 

[brblue]

+1 for knowing the TT length of the 2 frames first.

Other thing would be the handlebars used, in each case and their reach..

 

[Mike Prince]

Agree with points above, the stem is probably long to achive the best fit, not as a climbing aid.

 

[heffergm]

If you watch the good climbers they tend to be very upright, almost vertical (look at schleck) when climbing. Putting all your weight forward, especially during an acceleration, it's really easy to get the back wheel off the ground which is going to slow you down. I know because I tend to throw all my weight forward... Been working on staying back a bit and more upright. Keeps the back wheel on the ground.

I think the stem length is just related to fit.

 

[Ventruck]

It's also possible (but I'm too lazy to confirm this) that the horizontal dimensions of a 56 cm Madone and a 52 cm S-Works are much closer to one another as their nominal frame sizes would suggest. Point being, the connection between stem length and climbing prowess may prove to be nonexistent.

Interesting thought, nevertheless.

I looked into confirming it.

The 56cm Madone has a longer effective TT length than the 52cm S-Works SL3. Contador noted his Trek was too large for him at some point.

I also had the thought that the stem length was chosen to clear the bars from being hit by the riders' knees, but just playing with that thought myself with my 100mm stem, it's never happening - and I'm pretty certain my legs are longer than AC's (based on his BB-Saddle measurement of 74cm)

Thanks for everyone's insight so far. Guess best conclusion to draw atm is that such stem lengths are chosen for fit in terms of what feels comfortable for the riders out of the saddle...which I assume was created by trial and error as opposed to math.

The thought of keeping weight rearward to prevent slipping in the rear somewhat puzzles me as a longer stem would do the opposite. I guess by elementary deduction, this fit would then be a case of the arms as opposed to legs?

 

[wim]

Guess best conclusion to draw atm is that such stem lengths are chosen for fit in terms of what feels comfortable for the riders out of the saddle

Not saying this never happens, but I've never heard of out-of-the-saddle comfort being the driver for a stem length change. But as you pointed out, hitting your knees on the bar while out-of-the-saddle is a possibility (long femur). I know one rider who increased stem length to keep that from happening (later on, he got a longer frame).

For what it's worth, some riders (myself included) are sensitive to bar height when climbing out-of-the-saddle, with the preference generally being a lower bar. To appreciate how a high bar can cramp your climbing style, imagine the theoretical extreme situation of climbing out-of-the-saddle on a comfort bike—hands in front of your chest, elbows flexed 90 degrees. Not good.

 

[ssing20]

I looked into confirming it.

The 56cm Madone has a longer effective TT length than the 52cm S-Works SL3. Contador noted his Trek was too large for him at some point.

ETT length is meaningless without factoring in the seat tube angle. You need to compare Reach numbers which is the ETT if you had an imaginary 90deg STA.

"Seat and handlebar locations relative to the bottom bracket define your position" -- Cervelo Tech Presentation on Fit & Geometry

 

[Ventruck]

ETT length is meaningless without factoring in the seat tube angle. You need to compare Reach numbers which is the ETT if you had an imaginary 90deg STA.

"Seat and handlebar locations relative to the bottom bracket define your position" -- Cervelo Tech Presentation on Fit & Geometry

Point taken, but phooey: Trek doesn't provide ST length to me to do some math.

(Ironically?) wim, I just ordered another stem with a steeper angle for that very reason of being cramped.

 

[Richard]

ETT length is meaningless without factoring in the seat tube angle. You need to compare Reach numbers which is the ETT if you had an imaginary 90deg STA.

"Seat and handlebar locations relative to the bottom bracket define your position" -- Cervelo Tech Presentation on Fit & Geometry

Excuse me, but this assumes all saddles have the same rail length and all seatposts have the same setback. "Reach" on a particular frame compared to another may be a "constant", but that's why we have seatposts with varying setbacks, frames with varying TT lengths vs. head tube angles, fork rakes, stems with varying lengths, etc.

If your theory was so "correct", why does my Falcon with a 73.5 degree headtube angle, a 73 degree seat tube angle, a 56.5 top tube, and a 120mm stem, fit me as well as my Bertoni with a 72.5 headtube angle, a 72 degree seattube angle, a 56 top tube, and a 130mm stem. Plus, there is the issue of "bar reach."

Cervelo is talking about their frames and they are not the only ones out there.

Being the "bike fitter" in our shop, the thing that frustrates me the most are those that think "numbers are everything." I pay no attention to numbers, put the rider on the bike in a stationary trainer and go from there. Human beings are not "uniform" in either their physiology, their fexibility, their fitness, and particularly their leg-femur-torso-arm-neck-etc. I wish people would get over the notion that there is some "scientific" way to fit every rider onto every bike.

It takes time, feedback, obsevation, experience, and oftentimes a "refit" as that cyclist gains strength in "cycling specific" muscles (those "core" back and abdominal muscles that over time and miles takes pressure off wrists and arms.)

Sorry for the "rant", but in my "non-computerized, non-scientific" years of bike fitting, I've yet to have a customer come back and want to kill me.

 

[ssing20]

Excuse me, but this assumes all saddles have the same rail length and all seatposts have the same setback. "Reach" on a particular frame compared to another may be a "constant", but that's why we have seatposts with varying setbacks, frames with varying TT lengths vs. head tube angles, fork rakes, stems with varying lengths, etc.

If your theory was so "correct", why does my Falcon with a 73.5 degree headtube angle, a 73 degree seat tube angle, a 56.5 top tube, and a 120mm stem, fit me as well as my Bertoni with a 72.5 headtube angle, a 72 degree seattube angle, a 56 top tube, and a 130mm stem. Plus, there is the issue of "bar reach."

Cervelo is talking about their frames and they are not the only ones out there.

Being the "bike fitter" in our shop, the thing that frustrates me the most are those that think "numbers are everything." I pay no attention to numbers, put the rider on the bike in a stationary trainer and go from there. Human beings are not "uniform" in either their physiology, their fexibility, their fitness, and particularly their leg-femur-torso-arm-neck-etc. I wish people would get over the notion that there is some "scientific" way to fit every rider onto every bike.

It takes time, feedback, obsevation, experience, and oftentimes a "refit" as that cyclist gains strength in "cycling specific" muscles (those "core" back and abdominal muscles that over time and miles takes pressure off wrists and arms.)

Sorry for the "rant", but in my "non-computerized, non-scientific" years of bike fitting, I've yet to have a customer come back and want to kill me.

Calm down. You clearly don't understand what I am talking about. I am not accusing you or any other "fitter" of not knowing how to fit a bicycle to a rider.

Did you even read Cervelo's Geometry and Fit Presentation before writing???? I suggest you do. It'll make you a better "fitter". Guaranteed.

http://www.cervelo.com/en_us/engineering/tech-presentations/

I am talking about numbers and geometry and angles of frames, NOT about the whole process of what goes into a good fitting. Cervelo does a great job of explaining this geometry visually in their charts.

Cervelo is not just "talking about their frames". They are talking about frame geometry in general and even compare their frame sizing approach to Cannondale, Specialized and Trek. These are FACTS, not theories. Read the article, then comment.

Fact: You can have two frames with different ETT lengths with the exact same Reach if the longer ETT frame has a slacker STA. Fact. Page1 of the Cervelo Presentation proves it.

Being an engineer, the thing that frustrates me the most are those who think, "Numbers don't mean anything."

 

[perttime]

Being an engineer, the thing that frustrates me the most are those who think, "Numbers don't mean anything."

Ha! I am not an engineer but I believe that numbers are often very good for describing, and especially comparing, things... as long as you know what the particular numbers relate to :thumbsup:

I suppose they are not much good for describing a sunset, though