What's The Best Stem Length For You? | GCN Does Science

When road cyclists think about stem length, we tend to only take into account the effect it has on our position on the bike. But mountain bikers change stem length depending on the handling characteristics they want for their bike. So do different stem lengths change the handling of road bike? Dan and Si do some GCN science to find out.

Testing three different stem lengths, 80mm, 110mm, 140mm, Dan and Si perform two different skill challenges, a 'suburban challenge' and a descending challenge. Will there be any difference in times between the stem lengths?

Let us know what you think of the trend towards longer stems and smaller frames in the comments down below 👇

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[gcn]

Have you noticed the difference in handling with a different stem? Let us know 👇

[matthewboswell]

"6 inches Dan, that is huge" - does a lot for my ego, thanks guys

[michaelmcfadden]

As a shorter rider, changing my stem from 110 to 80mm provided big improvement to both comfort and stability, I spent years on the 110 and changed after a back injury - I was talked out of changing years ago by a guy in a bike shop for various technical reasons mainly around stability and i now know he was mis-informed because everything about my ride is better with the 80mm stem. The bike is a little more twitchy but that actually suits my physiology better, fighting the bars is more natural to me than reaching out for them.

[unreal]

I've gone from an 80mm stem the bike was spec'ed with a specialized roubaix 2017 to a 70mm stem. my times have been getting better, I feel less stretched out and uncomfortable and my confidence has increased because it just feels right.

[jerryavalos]

My bike fit was with a person with 14 years experience and who used the knee over pedal method if possible for both knees, but that isn't always possible since many people have one leg longer than the other. Setting saddle height had to the movement on the hips and making sure each knee produced the same minimal side to side movement. He ended up switching saddles using a woman's saddle which stabilized my hips and stopped excessive movement. The stem length and rise was all dependent on not just comfort, but achieving proper elbow bend with the hands on the hoods where the majority of the riding takes place. He also used a goniometer. I would have to say I came away from the bike fit with a much more powerful pedal stroke and felt more efficient. His advise on the bike didn't have anything to do with stem length or rise, but on striving to be and stay relaxed by dropping the shoulders. That was the best advice yet.

[ViveSemelBeneVivere]

I've learned more about bicycles and cycling during this Summer than ever before from Dan, Simon and the whole GCN Crew. Much appreciated. And now that I've been gathering the components to do a flatbar to dropbar conversion on my Specialized fitness bike, I was relieved to hear Dan advise that "If you are a shorter rider you'll need to go for a longer frame with a shorter stem" since I intend to swap out the 100 mm stem for shorter 80 mm to compensate for the slighly longer top tube. I'll let you know of observations in the reach and steering handling in due course.

[tfleishman]

Do not forger this. Short stems put the riders weight back weighting the back wheel more and taking weight off the front steering end. A balance of weight between the front and back wheel is what provides best stability and speed.The other thing that a short stem does is put more weight on the rear end and cause more saddle discomfort. The Italian set up has a rider in a normal position look down and see if you can see the front hub. If properly positioned your handlebars should obscure your front hub. bicycle 101 for stem length and position. All you need to do is calculate a proper seat height. cheers to you all the Viva-Velo Thomas Fleishman, Grand Junction, Colorado

[fofopads]

I use a 3 cm stem in my Emonda, because I was supposed to get 50 frame and got a 52 instead. It does feel harder to control on descent but climbing is so smooth and powerful. Coming from a 48 frame with a 120 cm adjustable stem

[beigemaster]

Idea for a “GCN Does Science” vid- MTB clips/SPD’s versus Road/SPD, SL’s- are the road ones really much more efficient?

[dvdp]

For me the (old) rule; “when on the hoods, the fronthub should disappear behind your handlebar”, works fine. Really don’t know what it is based on... Have been experimenting this last season and went back to my former stemlength. And yes, the hub disappeared behind my handlebar again! But.... the whole bikefitting thing is about trial-and-error! (A brand like Giant has a reason for NOT working with exact framesizes). Furthermore; the fit changes when you yourself get fitter!

[DYCARBINE]

1:14 That's not what my ex told me 😢😢😢

[yojerico]

I am glad it's not just me then I put a short stem on my gravel bike for quicker handling through descents but it took me two months to get used to the twichy feel and I actually had to practice cycling in a straight line I then found with a slightly lower grip I was able to learn to keep the bike steady.

[Bugumir]

My bike is one size too big for me so I went from 120 to 70mm. It's more nimble, more playful now, which makes city riding a joy, but less comfortable and less stable at high speeds which makes longer rides less enjoyable.
Anyway, my point is: get the frame size right so you won't have to compromise with the stem length.

[Nicoya]

I think the TDF could benefit from a few cone sections: maybe throw some in along long straights on TT segments to break up the monotony, or add some to the riskier descents to keep the speeds in check at the switchbacks.

[evgenysavelev]

In terms of how much you turn the handlebar to make a turn, there will be no difference (the angles are so small, that you don't notice the change in lateral displacement). However, it terms of how much your weight affects stability there is a big difference. With longer stem the application of force is further from the axis, so it will feel more stable.

You may also notice a change in braking, as the center of mass is now further forward, and thus your rear tires may grip less. If you make a drastic change in the stem length, you may flip your bike under extreme braking, as you are not used to the changed weight distribution.

[dlm]

The handling does change. My stock Cervelo S5 was a little too twitchy. I installed a 120 mm stem and the bike calmed down to a more "weekend warrior in the peloton" acceptable level.

[dlm]

I am 183 cm tall and my 58 cm Cervelo S5 was quite twitchy. I swapped out the 3T stem for a 120 mm Ritchey. The bike really responded well, much more stable and easier to ride in a group. I now have a 2017 Trek Domane and it doesn't seem to need the longer stem for stability. The bike is fairly stable as is. However, I am still considering a longer stem just to put me in the riding position I like. I have a tendency to feel more comfortable the farther forward I get.

[eagleeye]

It depends how long the top tube is . My tt is 53.5 that had a 110mm stem, I was too stretched out. The 90mm fits me perfect . If I had a smaller tt I could work with a 100mm stem .It's all about your reach and comfort level .I'm still slightly aero with my 90mm stem at -6° in the drops, if I wanted to be more comfy on a longer ride I'd just flip my stem at +6°

[snookerbg]

I've ridden an 80mm and a 11omm stem on the same bike for good bits of time; the shorter is not terrifying on descents. I guess it's getting used to the setup that counts.

[DavidCulshawmer-r]

4 years ago I got my 1st road bike, it had an 80cm stem that was ok on short rides but my back was sore after 10 miles, I then got a 60cm stem, that was really comfy but way too twitchy at speed, then I got a 70cm stem and wider bars ( 44cm) and it all came together very nicely, I can do 80-90 mile rides in relative comfort :)