What's the advantage of a very long stem?

[fiamme red]

https://cyclingtips.com/2019/07/pro-bike-peter-sagans-specialized-s-works-venge/

Sagan has always run a very aggressive position, at times requiring special frames from his team’s supplier. The chunkiness of the extension masks this somewhat, but that stem measures a whopping 150mm from center to center.If he gets custom frames, why the need for such a long stem? Perhaps he has unusually long arms? I don't think that a 150mm stem is commercially available.

[KonaSS]

He doesn't get custom frames. Those are stock frame sizes.

[fiamme red]

He doesn't get custom frames. Those are stock frame sizes.Is it just Sagan, or do most pros use 150mm stems?

[Mark McM]

Reach is a combination of top tube length, stem length and handlebar reach. Handlebar reach has been getting shorter the last few years, so to compensate, longer stems may be used. If you look at the photos, the handlebar on Sagan's bike has a very short reach (maybe only 60mm or so). If a more traditional handlebar with a longer reach was used, he would probably be using a 120mm or 130mm stem.


Edit: As a related note, it makes no sense to talk about stem length, without also considering handlebar (and lever) geometry. The stem just connects two members (handlebar and steerer tube), so the only correct answer to the question, "how long should the stem be?" is: "Long enough to connect the handlebar to the steerer." The position of the hands is the important variable, not how long the stem is.

[fiamme red]

Reach is a combination of top tube length, stem length and handlebar reach. Handlebar reach has been getting shorter the last few years, so to compensate, longer stems may be used. If you look at the photos, the handlebar on Sagan's bike has a very short reach (maybe only 60mm or so). If a more traditional handlebar with a longer reach was used, he would probably be using a 120mm or 130mm stem.


Edit: As a related note, it makes no sense to talk about stem length, without also considering handlebar (and lever) geometry. The stem just connects two members (handlebar and steerer tube), so the only correct answer to the question, "how long should the stem be?" is: "Long enough to connect the handlebar to the steerer." The position of the hands is the important variable, not how long the stem is.Thanks. But why not just use handlebars with a longer reach, say 75mm? Surely that is easier to find than a 150mm stem.

[pdmtong]

Reach is a combination of top tube length, stem length and handlebar reach. Handlebar reach has been getting shorter the last few years, so to compensate, longer stems may be used. If you look at the photos, the handlebar on Sagan's bike has a very short reach (maybe only 60mm or so). If a more traditional handlebar with a longer reach was used, he would probably be using a 120mm or 130mm stem.


Edit: As a related note, it makes no sense to talk about stem length, without also considering handlebar (and lever) geometry. The stem just connects two members (handlebar and steerer tube), so the only correct answer to the question, "how long should the stem be?" is: "Long enough to connect the handlebar to the steerer." The position of the hands is the important variable, not how long the stem is.
I was trying to set up a new bike with reach similar to my preferred.
Is there a standard way to measure the hood reach across the big three?

Bar reach, stem length, eTT I get. But how close (or not) is the reach of say Record 10, Force 10, DA 9170, Chorus 11? I thought I would go with where the web of my hand hits the hood but for the life of me cannot get a consistent measure to see if that is where I am gaining or losing 5-10mm. And yea, that 5-10mm is basically the delta in stem size chosen.

[Elefantino]

I'm sorry, but this thread title made me smile.

[ColonelJLloyd]

Thanks. But why not just use handlebars with a longer reach, say 75mm? Surely that is easier to find than a 150mm stem.

Doing that may achieve the same reach to the lever hoods, but would change the reach to the flat section of the bar.

[Mark McM]

Thanks. But why not just use handlebars with a longer reach, say 75mm? Surely that is easier to find than a 150mm stem.

Who knows? Maybe he just liked the shape of that bar. In any case, it appears the stem was available (at least to him, if it is a custom).

[Mark McM]

I was trying to set up a new bike with reach similar to my preferred.
Is there a standard way to measure the hood reach across the big three?

Bar reach, stem length, eTT I get. But how close (or not) is the reach of say Record 10, Force 10, DA 9170, Chorus 11? I thought I would go with where the web of my hand hits the hood but for the life of me cannot get a consistent measure to see if that is where I am gaining or losing 5-10mm. And yea, that 5-10mm is basically the delta in stem size chosen.

For levers, handlebars and saddle, duplicating exact measurements between different models can be tricky, because they (and we) are all shaped differently, and how our body interfaces with them will be different. For lever hoods, one common method is to rest a long straight dowel (like a broom handle) in the crooks of the lever hoods where the crotch of our hands would be placed, and measure the height and reach to the dowel. Again, not exact, but a close approximation.

[denapista]

FWB touched on this exact topic with the Handelbar shootout..

There's no real industry standard on how to measure reach on bars. The entire industry would have to agree on the method of measurement.

I rode a set of ZIPP SL TB bars and they were advertised having 87mm of reach. Fairwheels tested them using their method and got close to 102mm of reach. No wonder those bars felt super far stretched.

coming from BMX and my background of bike control riding dirt jumps and cement parks/pools, having a smaller frame with longer stem immulates that BMX feel. Easy to toss the bike around as it's underneath you. Maybe Sagan is going for that kind of feel with the 150mm stem?

[charliedid]

Don't a lot of sprinters ride super long stems? I recall Cav also riding a 150. Get out over the bike but not feel cramped when hammering and tossing the bike they way they do.

Aggressive fit for sure.

[cribbit]

Stem length is more than just reach though, it's also where your center of mass and hands are relative to the contact point of the front wheel.

[Lanternrouge]

I think we see pro riders with long stems since they tend to ride on smaller bikes than regular folks of the same size to get the really aggressive positions.

[FlashUNC]

Just got a frame with a 140 stem designed into the final geometry for the bike. Maybe the jerk can chime in on the particulars, but GCN also did some unscientific descending on varying stem length to show the variation in feel.

I'm a fan, but as others have mentioned its all interconnected and shouldn't be viewed in isolation.

[pdmtong]

I think we see pro riders with long stems since they tend to ride on smaller bikes than regular folks of the same size to get the really aggressive positions.
smaller bike has shorter top tube (hence longer stem) AND shorter headtube, the latter allows more bar drop and the aforementioned more aggressive position.

[Germany_chris]

Longer stems slow steering a bit

[Mark McM]

Stem length is more than just reach though, it's also where your center of mass and hands are relative to the contact point of the front wheel.

I think you'll find that this effect is smaller than you imagine. Merely increasing the stem length only moves the hands.arms forward, and has little effect on the position of the center of gravity. Moving the center of gravity in any significant way requires moving the seat. And even then, it doesn't make much of a difference. For each centimeter the CG is moved fore or aft, the front/rear wheel weight distribution changes by about 2%.

[Mark McM]

Don't a lot of sprinters ride super long stems? I recall Cav also riding a 150. Get out over the bike but not feel cramped when hammering and tossing the bike they way they do.

Aggressive fit for sure.

It is likely that the long stems are used because many sprinters assume very low positions (for aerodynamics). But just bending the upper body lower causes very extreme hip angles, which is not ideal for generating large amounts of power. So they rotate their bodies forward as well, to restore the hip angle. So they are both low and forward. Then to add to that, they'll often have to use a smaller than normal frame to get the handlebars low enough (and the subsequent shorter top tube), and they end up having to use a very long stem.

[Mark McM]

Longer stems slow steering a bit

Again, you can't consider stem length by itself, you have to also factor in the handlebar reach. The combined stem + handlebar length is sometimes referred to as 'tiller length'. A 150mm stem might be considered 'long' and an 0mm stem might be consider 'short', but 150mm stem plus a 40mm reach handlebar will feel and handle the same as 80mm stem plus a 110mm reach handlebar, becaus8e they have the same tiller length.

[charliedid]

I think we see pro riders with long stems since they tend to ride on smaller bikes than regular folks of the same size to get the really aggressive positions.

Agree but isn't 150 still an exception? Or is it?

[charliedid]

It is likely that the long stems are used because many sprinters assume very low positions (for aerodynamics). But just bending the upper body lower causes very extreme hip angles, which is not ideal for generating large amounts of power. So they rotate their bodies forward as well, to restore the hip angle. So they are both low and forward. Then to add to that, they'll often have to use a smaller than normal frame to get the handlebars low enough (and the subsequent shorter top tube), and they end up having to use a very long stem.

Understood. 150 might help stabilize and slow the steering a bit on what might otherwise end up a rather quick handling bike.

[charliedid]

Longer stems slow steering a bit

That might benefit the sprinters on these super quick bikes?

[wallymann]

https://cyclingtips.com/2019/07/pro-bike-peter-sagans-specialized-s-works-venge/

If he gets custom frames, why the need for such a long stem? Perhaps he has unusually long arms? I don't think that a 150mm stem is commercially available.

these days 150mm is pretty uncommon, almost certainly custom. 140mm can be found very rarely. fwiw...long stems look racey and sooo-pro! ;-)

For levers, handlebars and saddle, duplicating exact measurements between different models can be tricky, because they (and we) are all shaped differently, and how our body interfaces with them will be different. For lever hoods, one common method is to rest a long straight dowel (like a broom handle) in the crooks of the lever hoods where the crotch of our hands would be placed, and measure the height and reach to the dowel. Again, not exact, but a close approximation.

i use the same saddle, bars, levers on all (well, most -- i made lever concessions on my neo-retro bikes) of my bikes -- exact position is 100% reproduceable across all (most) of them! even carefully choosing my bikes for STA and TT for me this has required deploying a range of stems from 125mm to 140mm.

[berserk87]

In amateur racing, the theory was that a smaller frame could be used, which would weigh marginally less and be stiffer than a larger frame with a more conventional stem. That's what I understood back in the day. Pro racing doesn't have the weight issue anymore (a lot of teams have to add weight to bikes to comply with UCI minimums).

Modern stems seem to be much less flexy to me that the old quill stems, so using stem length to make up for frame size may work a bit better than it used to 30 years ago.

I ride a 130 currently. I had to back off of the 140 that I rode for years, as I don't have the flexibility that I once had. Now I'm used to the way it feels and changing would feel odd, and for no good reason.

I didn't know there was a 150 option. That's exceptional. I had to look hard years ago to find a 140.

[David Kirk]

Obviously a longer stem gives a longer saddle-to-bar reach and in some cases I suppose this is why pros use such long stems. One of the biggest reasons, that for some reason doesn't seem to have been brought up, is to shorten the front-center of the bike for a given saddle-to-bar number.

With a given reach using a longer stem means a shorter top tube, which of course means that the head tube has been moved rearward relative to the rider. This has a few real life effects - first is that it increases the percentage of weight on the front wheel which aides in handling and stability. Another key benefit is that it shortens the front center of the bike and allows the rider to be that much closer to the rider in front of them. I know its only a few cm but it adds up over time.

These are race bikes pure and simple and every little thing adds up....and a shorter front center is quicker when riding in very tight quarters.

dave

[FriarQuade]

Pros run long stems because the bikes are built for you and you want them a little taller and shorter. So they compensate by down sizing and running stems out of Shimanos fishing division

[josephr]

I think we see pro riders with long stems since they tend to ride on smaller bikes than regular folks of the same size to get the really aggressive positions.

this----a long stem lets him get as far on the front wheel as possible for those killer descent speeds.

[54ny77]

here's their 105 pole holder. i hear the dura ace version is really nice, better fit & finish.

http://www.stripersonline.com/image/id/1002557

Pros run long stems because the bikes are built for you and you want them a little taller and shorter. So they compensate by down sizing and running stems out of Shimanos fishing division

[bitpuddle]

He doesn't get custom frames. Those are stock frame sizes.

He used to ride a custom Super Six back when he rode for whatever that iteration of the team that was (Liquigas?). Essentially a 54 frame with the reach of a 56. This might just be an effort to have similar touch points with a stock Specialized frame.

[cribbit]

I think you'll find that this effect is smaller than you imagine. Merely increasing the stem length only moves the hands.arms forward, and has little effect on the position of the center of gravity. Moving the center of gravity in any significant way requires moving the seat. And even then, it doesn't make much of a difference. For each centimeter the CG is moved fore or aft, the front/rear wheel weight distribution changes by about 2%.

You're not moving the center of gravity, you're moving the front wheel.

Which I forgot to mention is also wheelbase length.

A 70mm stem vs 120mm stem is 10cm, or 10% according to your maths. That's huge!

[wallymann]

You're not moving the center of gravity, you're moving the front wheel.


incorrect. moving front wheel changes the relative location of the front wheel which affects CG location with respect to wheelbase.

in this simplistic example, you're moving from an evenly balanced 50/50 scenario to a very forward biased CG...all just by shortening the front-center.

[Mark McM]

You're not moving the center of gravity, you're moving the front wheel.

Which I forgot to mention is also wheelbase length.

A 70mm stem vs 120mm stem is 10cm, or 10% according to your maths. That's huge!

My example was for offsetting stem length and handlebar reach changes that produced constant tiller lengths. No change in front center/wheelbase, CG, or weight distribution.

On the subject of the affect of CG position or front center changes on weight distribution: In very rough numbers, a 1 cm change in CG (front center remaining constant) will change the weight distribution by about 2%. But a 1 cm change in front center (CG remaining constant) will change the weight distribution by about 1/2%. Changes in handling due to small changes in top tube/front center lengths are mostly due to changes in tiller length, and may also be due to changes in steering geometry (different size frames often have different head angles and fork offsets).