Shorter stem on a road bike

Z'mer · Jan 25, 2017

My take is steering feeling is most effected by the parameters you would expect - head angle, offset, trail, and also wheelbase. These parameters are different between race and endurance bikes, and change with frame size changes as well. Also the bar width can change between frame sizes.

I would also ask people to consider the steering feel change when going from hoods to drops, which are set back about 8-9 cm from the hood position. This would be the equivalent of using a 80-90 mm shorter stem.

As someone else has already posted, if you do the math, 2 cm changes in stem length has a very minimal change on the radius dimension from hand position to center of steering pivot, which is the size of your "steering wheel".
What people may be feeling instead is a higher or lower center of gravity based on stem length, which absolutely will affect the response.

masont · Jan 25, 2017

I run an 80mm stem on my 54cm bike. I've also been fitting people on bikes for six years, trained on BG Fit and Retul. I'm an inflexible middle aged white guy (with short for my height arms) so I prefer the stack of the 54 to the 52.

You steer a bike from your saddle by leaning. Not from turning the handlebars independent of anything else. Handlebar turn is more of a reactionary/balance issue than a steering issue. A 2cm shorter stem is not going to appreciably change your handling. Pay no attention to those who say it will.

I would trust your fitter over a bunch of random dudes on the internet. He's seen you on the bike. He does this for a living. He's not some random jabroni claiming without knowing any of the info you'd need to know that they're just trying to ditch stock.

And, if he gives you bad advice and it turns out it sucks, walk back in there, tell him the issues you're having, and I'd be shocked if he didn't fix it.

kbwh · Jan 25, 2017

Good fitter you have there, ejewels.

Thanks for the links, MMs. Unfortunately I do have to spread some rep before etc. But Boulder? Isn't that where most of the physicians Spesh use reside?

Srode · Jan 25, 2017

You told us you have a neck injury the fitter is accommodating with your more upright position temporarily on a road bike so it's not going to be a traditional looking fit, based on that alone I would suggest dimissing all the nay-sayers on the fit recommendation, unless someone comes up with a good technical reason an 80cm stem on a bike is wrong for some performance / safety reason and not just asthetics/tradition. I've used that size stem on one bike and didn't see bad effects from it.

I can think of a few reasons you fitter might put you on a 56 with a shorter stem than on a 54 with another cm one of which would be saddle position on the rails to get you where he wants relative to the crank. The taller head tube means you can get less bar drop with the maximum spacers under the stem. The 56 may also allow you a better more fit in the future once you adapt to the bike and get over your injury constraints. Its not all about the stem, there's a lot of other things to think about in a bike fit and you don't start with the stem to get a fit right and I certainly wouldn't be worried about an 80mm stem for a temporary set up while you recover.

pedalbiker · Jan 25, 2017

.....

pedalbiker · Jan 25, 2017

ejewels said:
Honest answers by who though, thats the question. Pro bike fitters? You're right, I don't want to hear assumption-fueled answers by people that don't know my proportions or body dynamics. Is that wrong? I also don't mean to sound confrontational. I just really want to see people's views on running a shorter stem.

Running that short of a stem is something I would not do.

There you go.

Jay Strongbow · Jan 25, 2017

duriel said:
Changing from a 120 to a 80 changes the dia of the lever arm about 2mm, if you can feel that you are a master bike handler.

um, but it changes weight distribution by 4 cm. Just move your hands back 4cm next time you're on a fast curvy road and you can decide for yourself if it makes a difference.

pmf · Jan 25, 2017

Jay Strongbow said:
um, but it changes weight distribution by 4 cm. Just move your hands back 4cm next time you're on a fast curvy road and you can decide for yourself if it makes a difference.

I like how some folks here claim to be able to tell the difference in +/- 2.5 mm in a crank arm length, and not +/- 20 mm in a stem length.

kbwh · Jan 25, 2017

Fact: The claim is that the steering response is not negatively affected.

But I guess facts are not valid currecy these days over there.

Jay Strongbow · Jan 25, 2017

kbwh said:
Fact: The claim is that the steering response is not negatively affected.

But I guess facts are not valid currecy these days over there.

The claim that someone can feel the difference is no more or less valid than someone saying they can't. Some can some can't. That is the fact.
Why can't you just accept that different people notice different things? Do you think there's some motivation to logging on the internet to lie to people about being able to notice a difference in handling with different stems?

ejewels · Jan 25, 2017

Thanks everyone for their help. Looks like my fitter was just doing his job and I need to work on my flexibility. At first I was a little concerned by the initial responses, but after we all got more info it seems to be OK. And one poster talking about the 56 giving more options and better for my condition was right... my fitter even discussed it.

bvber · Jan 25, 2017

MMsRepBike said:
Racing cars have small steering wheels for this reason. So by definition it will make your handling more twitchy as they call it, or precise maybe, or faster, however you want to say it. A long stem is like a big steering wheel, like a bus. Slower, more stable, more input needed to turn.

Racing car steering wheel size vary roughly 16" - 11" depending on the type of race. Also, there is different rate of steering resistance and the degree of turn. It's much more complex than bicycle steering.

Z'mer · Jan 25, 2017

Jay Strongbow said:
um, but it changes weight distribution by 4 cm. Just move your hands back 4cm next time you're on a fast curvy road and you can decide for yourself if it makes a difference.

I agree weight distribution is critical in turning. But a great percentage of the front back distribution is fixed by the position of the saddle. Changing your upper torso height, and dipping the shoulder / side lower has a much greater effect than absolute hand position.

The torso height and side dipping can be facilitated by either bending more at the elbows, or going to the drops. Where the hands are maybe 8-9 cm further back than on the hoods.

velodog · Jan 25, 2017

Handlebar width probably has as much influence on front end leverage as stem length but I don't remember any discussion here about bar width influencing the bicycles handling.

Well except handlebar matching shoulder width.

ejewels · Jan 26, 2017

masont said:
I would trust your fitter over a bunch of random dudes on the internet. He's seen you on the bike. He does this for a living. He's not some random jabroni claiming without knowing any of the info you'd need to know that they're just trying to ditch stock.

Thanks for this response. I originally was trying to convey this but unfortunately people are quick to assume the worst. Human nature, I guess. Glad things worked out.

Jay Strongbow · Jan 26, 2017

velodog said:
Handlebar width probably has as much influence on front end leverage as stem length but I don't remember any discussion here about bar width influencing the bicycles handling.

Well except handlebar matching shoulder width.

you're right, I imagine, but the thing apparently a lot of people don't get is that the topic has virtually nothing to do with leverage and has to do with weight distribution.

Those of us that feel the front wheel is less 'planted' thus more twitchy with a short stem feel that because we have less weight over it and/or that weight is moved back.

There's a reason most people instinctively don't bomb down curvy hills sitting up hands back and on the tops and it's not just to get more aero.

velodog · Jan 26, 2017

Jay Strongbow said:
you're right, I imagine, but the thing apparently a lot of people don't get is that the topic has virtually nothing to do with leverage and has to do with weight distribution.

Those of us that feel the front wheel is less 'planted' thus more twitchy with a short stem feel that because we have less weight over it and/or that weight is moved back.

There's a reason most people instinctively don't bomb down curvy hills sitting up hands back and on the tops and it's not just to get more aero.

Even someone riding with a less than "optimal" length stem can get long and low by getting in the drops. I've seen too many out there with the bars so low and far forward that they riding on straight elbows and the bar tape in the drops looks as if its never been touched.

This whole thread was started by someone who suffered a neck injury and he is given advice without knowledge of the injury. Is that injury going to result in permanent inflexibility, or temporary? If temporary, how long is that? Short term temporary may mean that he can make a smaller frame work but long term may mean a larger frame now and a possible smaller frame later.

And as far as long and low, and aero for that matter, what does that mean if he doesn't race? What is wrong with being comfortable on a bike in a more upright fashion and getting in the drops to ride into the wind or bomb some corners.

There are too many cyclist out in the wild with slammed stems and looong stems because of fashion and not what is optimal for them. What good is a slammed or long stem if the cyclist can't bend their elbows or get into the drops because it is uncomfortable to the point of pain?

Jay Strongbow · Jan 26, 2017

velodog said:
Even someone riding with a less than "optimal" length stem can get long and low by getting in the drops. I've seen too many out there with the bars so low and far forward that they riding on straight elbows and the bar tape in the drops looks as if its never been touched.

This whole thread was started by someone who suffered a neck injury and he is given advice without knowledge of the injury. Is that injury going to result in permanent inflexibility, or temporary? If temporary, how long is that? Short term temporary may mean that he can make a smaller frame work but long term may mean a larger frame now and a possible smaller frame later.

And as far as long and low, and aero for that matter, what does that mean if he doesn't race? What is wrong with being comfortable on a bike in a more upright fashion and getting in the drops to ride into the wind or bomb some corners.

There are too many cyclist out in the wild with slammed stems and looong stems because of fashion and not what is optimal for them. What good is a slammed or long stem if the cyclist can't bend their elbows or get into the drops because it is uncomfortable to the point of pain?

I think you're projecting some meaning into my comments that simply wasn't there or intended.

I notice quicker handling with a shorter stem. Period. I'm not trying to tell anyone they need to be aero, look 'pro' or anything like that.

velodog · Jan 26, 2017

Jay Strongbow said:
I think you're projecting some meaning into my comments that simply wasn't there or intended.

I notice quicker handling with a shorter stem. Period. I'm not trying to tell anyone they need to be aero, look 'pro' or anything like that.

I'm not projecting anything at you, I'm saying that optimal handling can be achieved with a shorter stem.

The rest of my statement is more about when others follow information blindly to achieve what they have been led to believe is the "Holy Grail".

kbwh · Jan 26, 2017

Jay Strongbow said:
The claim that someone can feel the difference is no more or less valid than someone saying they can't. Some can some can't. That is the fact.

Not even an alternative fact.

Why can't you just accept that different people notice different things?

Where did you get that from?

Do you think there's some motivation to logging on the internet to lie to people about being able to notice a difference in handling with different stems?

Not in your case.

Still: It's weight distribution, trail and wheel base that are the main parameters for how a bike handles. Stem length is sub.

Shorter stem on a road bike

Z'mer

masont

kbwh

Srode

pedalbiker

pedalbiker

Jay Strongbow

pmf

kbwh

Jay Strongbow

ejewels

bvber

Z'mer

velodog

ejewels

Jay Strongbow

velodog

Jay Strongbow

velodog

kbwh

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