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

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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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Leave us a comment below!

[@gcn]

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

[@user-rc2um5lk6s]

Yes I have

[@dEPICklopfer]

Yes, i Have, Changed the Steams the last 3 Years, every year an all of my Bikes. First just because of an comfort aspect, than because of the Handling affect aswell Started with 90 mm an the Roadbike and Mountainbike, went to a 100, and now i´m at 110. The funny thing, it got more and more Comfortable, the Longer i went, and i got faster. also tried a 120mm stem an one of my MTB´s , but changed back to the 110 since it Handled better

[@dEPICklopfer]

And, if you think about Stem lengts, you shoult have a look at the Shape and measures of the Handlebar aswell, specially on a road bike

[@maniac0303]

I am using a 110mm stem on my Stevens Ventoux Disc. I checked it with a 130mm stem and it was way too long for me. Especially on the hoods, because of the very big Shimano hydraulic disk brake ST-RS 685 brake levers. But on my older Carver Evolution aluminium road bike before 130mm is absolutly perfect. 110mm is way too short on this bike... My conclusion is that it depends on the different geometry of each bike frame...

[@kargs5krun]

+Global Cycling Network. Geez chaps, didnt you watch yer watts on these runs? (half kidding) No really, yer speed appeared to be a factor too as you both went faster on 140mm vs. 110mm, yet blazed on 80mm. WTF? Redux in the works??? #speedkillsitMates #speedmatters :-0

[@matthewboswell2494]

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

[@victorcordon3411]

6:35 just a totally different animal down there

[@victorcordon3411]

6:40 too

[@Forgotten_Boy]

"Depends on where you measure from." 🎉

[@michaelmcfadden4397]

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.

[@lilhavin]

How tall are you? I'm 5 feet and 6.5 inches I just ordered a 110mm stem after riding with a 90mm stem. I hope it isn't too long of a reach. (I do plan to drop in stack height though)

[@unreal1066]

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.

[@dreyn7780]

Realize You've already installed a lever onto the steering post. You're using leverage to add more power to turning the steering post. The Stem is a lever. It's got NOTHING to do with muscle tiredness. You're adding more power to turn the steering post. So, You've ADDED 7 more power units to assist you to turn the steering post in cornering. You've ALSO chosen a lever angle of ZERO degrees, which causes your steering performance to be extremely aggressive. YOU must turn a lot to get the bike to turn. Once you start the bike turning, it turns a lot in a short amount of time. Very aggressive steering performance. You're bike DOES NOT feel safe and comfortable. We own road bikes with adjustable Headstem angle. You're running the MOST powerful leverage setting on your bike. Your bike moves from side to side VERY aggressively.

[@LittleBU96]

@@dreyn7780 its for comfort…….

[@bradblackwell6597]

@@LittleBU96 boom roasted

[@Exaggerates]

How tall are you

[@Paulklampeeps]

​@@dreyn7780 will that be the same if the bike is long for him?

[@jerryavalos9610]

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.

[@tfleishman1]

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

[@joemaciulla3307]

Thank you.

[@mowhugspanda7769]

That’s why I’m always having a spike rear problem. Because I’m using short stem and I’m 116kg. I will use long stem. Thanks 🙏

[@hayata1191]

@@mowhugspanda7769 did it help?

[@brettrueter3370]

When I have a short stem I lean farther forward, putting more weight forward

[@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.

[@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.

[@ericbaguyo2474]

I’m ridin a fixie straight 52 and I’m a short rider 5,6. From 110mm my back, leg, wrist sore in a 100km ride. But now using 70mm and it feels great though the handling is twitchy.

[@dvdp4513]

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!

[@raulguedes7247]

exactly, i just remove and add spacers according to my beer belly

[@fofopads4450]

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

[@DYCARBINE]

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

[@NielsHeldens]

Garrubrations kzbin.info/www/bejne/aquvl3akfLuYgpY

[@stephenmoore7882]

She knows it's better with an 8

[@SunshineCarpetCleaningAZ]

Hahahahaha

[@mikefule330]

It's not just whether it's six inches, of course. Was it angled down or up at the time?

[@maxw5229]

@80% nomore fun for you bigboy

[@yojerico5856]

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.

[@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?

[@oreosaysb00]

beigemaster86 I use mtb pedals for my road bike because I commute so makes easier to walk in

[@joestevenson5568]

well, they are significantly lighter if nothing else - so it's a resounding yes.

[@DurianriderCyclingTips]

@Joe no that much weight doesnt mean anything mate! xD Ive been using xc shoes and pedals for 20 years and NEVER been dropped because of them.

[@HeathyRoidz]

Durianrider Cycling Tips cuse it’s only 200g different with shoes and mtb pedals... not everybody is able to afford 20 bikes under 7kg like u do

[@simonr7097]

@@joestevenson5568 Shimano has some one-sided SPD pedals (ES600) that are only 50 grams heavier than their Dura Ace SPD-SL pedals. I'll take the convenience of being able to walk in cycling shoes, plus having the same system for my commuting and road cycling bikes.

[@rehmsmeyer]

9:02 - That bike is fking beautiful

[@eagleeye8916]

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°

[@eddiearimas2201]

I like what you said is it still working? I didn’t listen to my mechanics to go less than 90. Refitted myself then worked on stem length 6 degree Much research followed even went to 60 then 70 after trying 80 Back to 80 not contemplating frame size or bike geometry I ride Felt VR6 and upgraded it wheels, pedals aero handlebars and a wee bit more Back to 80 now but considering my fitness level now but definitely understand if reach and fit 58 might be too large and I’m 6 ft tall Original 110 installed on an extreme downhill permitting my bike 43mph recorded Uphill an ant could have kept up. It was still hard to control going full gas downhill with 110 I haven’t tried this w 80 yet but it’s what I have for now and hope less twitchy so to speak. Than 70 Is the position on the bike specifically handlebars that compensate for more control with a shorter stem like 80 on a downhill experience? Eventually thinking a 90 stem due to reach because another bike isn’t in the picture for some time. And 90 would be the least as suggested from what I’ve researched. Ride on my friends, I’ll be there to💫🥰 Stay safe and Ride🎈

[@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.

[@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 :)

[@callumsmith338]

80cm stem? No wonder your back was sore!

[@neutronshiva2498]

@@callumsmith338 Why? Was it too long?

[@Tokino_]

@@neutronshiva2498 "cm"

[@vixantenna]

😂😂😂😂😂😂@@callumsmith338

[@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.

[@CommaCam]

A while ago I switched from 120 to 90 for comfort reasons, and I've gotten used to the extra responsiveness over time. It did feel a little twitchy at first but I actually really like it now.

[@leeelliott3704]

I use a 60mm stem on my road bike and I prefer it to a longer stem.

[@salnichols94805]

The 85 feels fine on my small AWOL with it's more upright position. I have a 110+ on my 54cm Merlin. I originally spec'd it with a 90 but it scared the pants off of me on descents. Any twitch would set up a harmonic ...terrifying.

[@sisaktamas]

Yes sure, I agree. And comfort is paramount, just like Taylor Phinney said on this very channel.

[@damien847]

"It all depends on where you measure from..." Something men have been saying for millennia.

[@dreyn7780]

Wrong. We're tuning NOT measuring. We're not gossiping either.

[@dlm8751]

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.

[@evgenysavelev837]

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.

[@jakegarrett8109]

I think the "wanting to rail" was because you are leaned forward, putting more weight on the front wheel.

[@dlm8751]

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.

[@julianpye5971]

I tried a longer stem (120mm instead of the 100 that came on the bike), to try to give my ridiculous gibbon arms a bit more room. I did find that I had to shift my weight forward a touch, as there was slightly increased speed wobble on downhills with less weight directly on the bars. Definitely found the handling smoother once I'd made the adjustment, though.

[@anykarthik]

I ride a Ridley Helium sized Medium. It's a bit long for me (I'm all legs... no torso to speak of), so I run an 80mm stem. And the head angle is a pointy 73.5 degrees. I've got about 8500 miles on this setup and I love it!

[@gmt198]

If you shorten the stem, surely you should widen the bars? That's what happens in mountain biking. It's true that the bike frame design counts into this too, but the wider bars can mitigate the shorter reach somewhat and make it less twitchy by also restoring some of the leverage lost in the stem.

[@jayarnett9082]

So. Much. Innuendo. "It depends on where you measure from."

[@mikewy192]

These guys do a great job. Really relaxed and amusing and informative. Enjoy this channel esp. due to these two. Great stuff.

[@cristianvizcarra1657]

GCN, where can I find out more about Tom Sturdys findings in regards to "bigger frame, shorter stem" theory. Thank you

[@righteousone8454]

Short answer: best stem is the stem that feels right. That's it.

[@dreyn7780]

You speak as if it's a plant. The Headstem IS a lever bar. You're adding the power of leverage to your steering power. You're increasing your power by using leverage to add more power so you can easily turn the bike. You adjust the leverage power so you can fine tune the aggressiveness of the steering performance. You tune the steering Stem leverage power so the bike is faster at high speed OR low speed. YOU chose the performance aspects.

[@willwhite1987]

@@dreyn7780 what are you on?

[@dreyn7780]

@@willwhite1987 you’re not going to skip over introductions.

[@tszabon]

I have just changed stem from 110mm to 80mm, it's more comfortable for me, I have no numbness in my hands but it's a bit harder to keep straight line when I'm holding drops.

[@GiedreSarkunaite]

Ride 110mm stem and can't fault it. Was petrified in Tenerife on a rental bike with 80mm stem, just about survived. It will go a lot to say men will ride differently to ladies but personally love a more stretched position and will consider going with 120mm on new frame.

[@kennethsmith4202]

My triathlon bike was twitchy and unsafe with a 95cm stem. Switching to a 110 stem made the bike safer and faster (because I can go downhill with greater control. Would really like to try a 120 stem to see what that would be like.

[@mlee6050]

95cm is insane lol

[@stillededge]

6'3"...just went from 110mm 17° to 80mm 6°. Totally agree with "more nimble"; I feel "locked in" in the corners. Bike fits much better, easier to get low on the drops, less stress on the low back & arms, more relaxed & supported. It LOOKS stubby is the only downside I've got so far. And I haven't BLAZED downhill cornering yet.

[@MattSezer]

I use a 80mm stem on a 55cm frame with somewhat aggressive racing geometry to make it more comfortable for causal centuries. I could have just got an endurance bike, but it's nice to have the option to throw a longer stem on for faster and shorter rides. There's definitely a difference in handling from the 110mm stem that the bike came with. I actually didn't think the 110mm stem was responsive enough, whereas I think the 80mm is a bit too responsive. I think a 90-100mm stem would probably be the sweet spot in terms of comfort and handling for me with that bike.

[@leeoien8512]

I was thinking about increasing my stem length just a tad from 100 mm to 110 mm for a slightly more aero position. The first thing I did was to check out the GCN archived presentations on this topic! Thanks for the insights and the resource! Since my bike is several years old it looks like I can pick up a the Bontranger RXL in the 110 mm length for less than $40. Not too expensive to experiment with!

[@seattlegrrlie]

What size stem "should" you ride? The one that came with the bike.

[@DaveWarnock]

If a longer stem gives more stability and better aerodynamics while a shorter is potentially more manoeuvrable then why not an adjustable stem connected to your electronic gears? As you change up through your gears the stem gets longer. As you change down (when aerodynamics are less important and a more upright position with quicker handling would be good) the stem gets shorter.

[@davidjohnson8054]

I'm so jealous of you guys with those totally flat stomachs!

[@noahmills3302]

Gotta love the Emonda

[@sbcc01]

40+ years of cycling & experimenting, has left me with very similar stack/reach/top tube/head tube dimensions on 8 road bikes all with 13cm stems seems to work for me!

[@dreyn7780]

Well you're not tuning the bike for any part of the race or any part of the road. You're simply disrespectful to bike designers and engineers. A Headstem IS a lever bar. It increases the amount of leverage power onto the steering post. YOU adjust how much leverage power is needed to achieve your steering performance. Clearly You've decided to remain uneducated. You've increased leverage on the steering post with a 13cm lever bar. Obviously set at a boring angle of zero degree (Which is at 90 degrees to the steering post). So your steering performance is very aggressive steering. Basically you have an untuned race bike. It will do nothing well. You haven't improved the bike for any aspect of the race or road. It's average performance everywhere it goes.

[@glynnsixsmithhookings2941]

Thanks really helped me, changed from 70 to 110 on my boardman 8.9, huge difference to handling and most important comfort.

[@mosher6264]

Putting forward the saddle and adding 10-20mm to the stem is a good option? I feel much stronger when i sit and pedaling more forward.I’m 177cm and i have a size L bike with 100mm stem.

[@cup_and_cone]

Forget the stems, I want that Pro Stealth saddle.

[@NathanBudd]

This is actually really interesting and useful! When I bought my bike 2 years ago, I was convinced to buy a medium, whereas now, I know more about bikes and fit, I was considering getting a smaller stem. I hadn't considered the twitchiness of the 80mm, so I may now rethink this.

[@briandigriz5872]

I found a big improvement with mine - Cube Peloton 56cm - going from 100mm to 120mm. I feel much more confident cornering now.

[@stinkyfungus]

My 56cm emonda originally had a bonteger 100mm stem and 42cm bars with like 95mm reach. I hated that bar. Too narrow for my shoulder width, and felt like a solid piece of aluminum... very hars h Went to a carbon 46cm Enve bar with 12* of flare And 80mm reach, Felt so nice, but my cockpit felt short Went to a 120mm stem. Perfecto. As for "the designers know what they are doing" for stem length... nah... they build mass production bikes to fit the "average" person in the middle of the fit range for each size. Of you are on the high or low side of the fit range or are an "overlaper" like me (at 6'0" I can fit a 56, but I can also fit a 58) you might find the touchpoints a wee bit off for you.

[@SwedishHouseFifa]

This should be an olympic sport! And i'm talking about the carpark race!!

[@joehiatt1992]

Cars have there own parks?

[@guymorris1963]

SwedishHouseFifa There might be massive amounts of systematic doping.

[@brendonnoble3296]

For all those cyclists who are between sizes, made a mistake, or inherited a wrong size one playing around with stem length is about the cheapest way of improving the handling.

[@PrabuddhaDasGupta1966]

I have myself also found that a short stem makes the handling more twitchy. What I am more keen to know is what handles better in the real world handling situation, a short stem long top tube combination or a short top tube long stem combination, where both are the same total length.

[@LurkyMclurker]

I like the idea of this test but I think you really need to use different size frames so you can judge the effect of stem length while keeping the same overall reach.

[@LeSpocky]

So at 1:54 he says "from center to center", but all that was already forgotten at 2:29 when the graphics guy had to make well the graphics. Details. So important! Anyways, I bought a used Trek CrossRip LTD 2016 recently and it came with a 90mm stem. I switched to an 80mm after a few weeks and was surprised how big the difference in comfort is. Just 1cm less reach and now I can handle all hand positions with ease. It's definitely worth it to try different stem lengths, if you're slightly uncomfortable and have the chance to try!

[@pirminborer625]

Geometry and frame size, tire widht, stem lenght and width all affect handling. With an already agile geometry and small tires, decreasing stem lenght can make it too nervous whereas with bigger tires and head angle, a shorter stem can improve handling without making the bike feel unstable.

[@TheJmbf10]

Been using a 40mm stem on my road bike for years and it makes the fit of my bike super comfortable and I got used to the handling. Going to a long stem feels really weird now.

[@dreyn7780]

The Stem is a leverage bar. You turn the handle bars and the Stem adds massive leverage power to the steering post. It's got nothing to do with muscle tiredness. You wanted lots of steering power so the design engineer installed leverage power onto the steering system of the bike. They stuck the lever at the maximum 90 degree angle for Maximum turning force on the steering post. It's got nothing to do with comfort. You wanted power, you got it.

[@diealeisterlive]

@@dreyn7780 u dont know jack shit xD

[@yoda112358]

This test would be much better if you had found bikes with varying top tube lengths, so that you could adjust the stem length while keeping the overall reach the same.

[@AllIsWellaus]

Pro5edited that was hilarious. "Six inches, that is huge!"

[@workingguy6666]

Meanwhile, I'm riding a 70mm + 25 degree stem on my road bike - I had to switch form the 90, 6-degree I spec'd on it as I find that I no longer have the flexibility in the lower back that I used to. Now that I've been riding it for about a year, I am researching an 80mm ~17-degree stem. I think I can stretch a little bit more now. Disclaimer - this is a very flat area, so it just doesn't have the opportunity to become too twitchy on descents.

[@TheJawnYo]

Put aside fit, no question a longer stem means the rider has to use more of the small force it takes to turn the steering post which makes it more stable, less sensitive to slight changes in input. And at speed those forces required are higher to overcome gyroscopic inertia of the wheel

[@NielsHeldens]

Stems - it‘s not about the length, it’s about how you use it.

[@petarstoisavljevic4230]

30mm can mean alot- from pain to pleasure

[@yojerico5856]

Yeah my wife has been telling that for years lol

[@CommaCam]

And where you measure it from.

[@luismedeiros7139]

And where you measure it from.

[@Sills71]

says the man with a short stem

[@fredericchopin2453]

"That's like 6 inches down, that is HUGE!"

[@dreyn7780]

It's called the wrong frame size.

[@paulsherwood5864]

I have a 90mm stem, and I love the responsiveness. Especially when there's an unexpected blemish in the road.

[@segway2613]

Smaller riders that are faced with the 'dilemma' of long bike short stem vs short-bike long stem should look into the Reach of the handlebars themselves aswell. Good ones range from 65-80mm with Specialized making one in 65mm Reach.

[@DavidUKesb]

I think there should be a Tour de France stage featuring some weaving in and out of cones. And also a descent TT.

[@LeoInterHyenaem]

Have you a practical chain stay length comparison video? And symmetrical vs asymmetrical chain stay comparative review?

[@mathijss.8347]

I think handlebar ''width?'' (sry for spelling) would be way more interesting

[@clockworkchaos784]

Well? A combination of shorter stem + wider bars vs longer stem + narrower bars should negate the twitchiness/sluggishness, ergo comes down to comfort vs aerodynamics...

[@mathijss.8347]

Yep, but short bars should also be mroe aero in principle

[@af252]

Mathijs S. already done that one m8

[@NikFowler]

Yeah, but mountain bikers now have wide bars but SHORTER stems. What's the difference between that, and a longer stem and narrower bars? Surely they cancel each other out?

[@clockworkchaos784]

The reason MTBs have shorter stems *(with exception for climbing) is to move their weight further back so as to reduce the chances of flipping headlong over the bars when going downhill thus necessitating wider bars to compensate for twitchiness. Of course wider bars increases the chances of smacking your hands off scrub.

[@labcoat22]

You mentioned a great topic at the beginning of this video. What is faster a small fram with long stem and laid back seat post or a proper fit frame. Or what is faster fit French fit, Eddie fit or compative fit

[@PBRStreetgang66]

what a great clip - well scripted, great visuals - glad to see you make the product promo clear and obvious. THANKS

[@marcustaylor670]

On my hardtail 29er mountain bike I like a 110mm stem (up from stock 75mm), I use a 75mm (up from 50mm) on my full suspension. I have a 130mm (up from 110mm) on my road bike but the frame is a bit small for me. I'm one of the fastest people at my local forest on a few Strava sections on my aluminium boardmans so I must have my setup somewhere near. I pretty much bought a load of stems and kept swapping them around as well as raising and lowering stack heights until I was happy. Most pro XC riders use long stems.

[@kevinfox5594]

TBF as someone who's mountain-biked for years, short stems only really came in once head angles relaxed and bars widened - I have thrown a 45mm stem on a vintage mountain bike with steeper head angles and it was a bit new trousers time

[@zaheerkader7426]

110 to 120 mm stems are the sweet spot for me personally.. Smallest frame possible with a longer stem is my preference

[@Rose.Of.Hizaki]

I have a Cube Attain GTC Race in a size 56 frame. I bought the bike based on the manufacturers recommendations of rider height. Ive had the bike since 2016 and havent touched the stem till now. I always thought that the frame was too big and maybe i should have gone with a size 54 or 55 frame so I didnt feel so stretched out. Yesterday I swapped out the stock 100mm stem for a 90mm Deda and while the bike was slightly more twitchy for aggressive out of the saddle efforts. Regular in saddle efforts and cruising were a lot more comfortable and i could sit slightly further back on the saddle a bit more. My back and shoulders were a lot less fatigued after my regular ride. Next step is changing the stock handlebars (which i think are 42cm) for a 40cm one but that wont be for a while as I recently just had new bar tape put on. Bike fits are expensive but at least you'll get a list of measurements for future reference to help you if you cant physically test ride the bike you want to purchase. Always test ride the bike you want to buy if possible.

[@ZOB4]

I ride a 49cm frame with an 80mm stem with no spacers under it as a 5'3" male rider (1.6m), and that is plenty long for me. The only issue I have with my fit is that I wish the drops on my bars were traditional instead of ergo. The ergo grip has my elbows about as far back as my hips, where I'd prefer to be a little more stretched out, and even with my levers as close to the bars as possible, I can still barely reach them with my longest finger in the ergo position on the drops. A 140mm stem would have me laid out like Superman if I were on the hoods, and completely unable to use my drops. I feel Emma Pooley's pain on the fit side of things. Regarding the longer frame with a shorter stem - that is good advice. Toe overlap is definitely real on small frames. I can't turn my wheel more than about an eighth of a turn without having to pay attention to which foot is forward. My next bike will probably use 650b wheels unless it's a TT bike where I don't need to worry about sharp turns or track standing.

[@bartvisser84]

Your video editing are really great these days. Seriously loving he whole experience.

[@MrBenjaminkruegereu]

Frame XL, Stem 60, reach 69, low drop.Typically a L Frame Rider.Best results with the XL so far- BUT: I am mainly an Enduro Racer with a roadie spleen, feel safer on short stems at high speeds.A roadie tested and got scared of my setup-i got scared of his M/L with 120mm and 89 Reach- far to inresponsive and unprecise for my style. It is just what you are used to and expect of it.

[@leedorney]

I used to ride a 170mm - YES i found one.. 😮 - bike frames are archaicly backward in design and I've always thought off-the-peg lean too far back + have too short a top tube, so i got a custom steel and now I'm happy ! 😉

[@jeffbrunton3291]

I don't get this. The bike including stem needs to be the correct length. So this is mainly a test of how a good fit compares with a bad fit. Longer stem stretches you out so more aero, which accounts for some of the time difference A proper test would be to use a 140 stem vs a 80 stem, on bikes that are 6cm different in top tube length. I have a 140 stem on my cyclocross bike, because the bike is slightly small for me and a new stem was cheaper than a new bike

[@nickschelvis2173]

I ride an S-work venge Vias with a zipp sl sprint 130mm stem and the S-works aerofly handelbar(flat one) and the first thing I noticed is that the long stem handels much smoother than the shorter one. and in the criterium I ride you don’t need to do those slaloms so that will not be an issue;)

[@pirminborer625]

Changed stem length from 110 to 90 on my orbea orca. What a difference with 28mm tires. Cornering much better, more progressively and nimble. I wouldn't do that on 23mm.

[@chrisjenkins1]

Ok 'that's what she said' X 15

[@Bartooc]

More like that's what she never said to a 6"

[@frankdavis9923]

Up to very end good advice. What the bike mfg. stem length is for avg. rider proportions- ie. if upper body / arm length is longer than normal longer stem is needed. if shorter then shorter stem. That assumes both riders are same height. I am 5' 10 -70cm but 6' arm length wide shoulders (54" chest) - shorter than normal legs. so sloped geometry was a God send for me. Have a Colnago EPS size 54s with 140 stem. had a 130 stem felt cramped even with stem slammed. . Been riding over 45 years as an adult. Even my tandem has 130 stem length but stem not slammed for better control. single bike and tandem within 5 mm on reach- but wider 44 cm bars on tandem and about 10 mm less drop to bars- for better control of a over 400# tandem team. Love your video's. On rails on down hills - esp. great for tandem.

[@gastonmacmillan4849]

Longer stem, more weight forward over the front wheel, should be faster. Still, fit and comfort rule the day for 50+y.o. Folks like me.

[@wecf1411]

Gaston MacMillan hmm never thought of it, more weight over the front wheel makes it easier on climbs. I might invest in a longer stem, just to have a longer stem.

[@TheSaturnV]

I still follow the Greg LeMond rule: Down in the drops you should be able to just see your front hub just behind your handle bar tops. Easy!

[@Raptors0524]

TheSaturnV if that is the rule then My stem is too long. But I don’t wanna go shorter😂. I am hoping I can grow into my stock stem. My local bike shop suggested I go down 4 CM. I did not buy an aaero biketo not be aero 😂

[@maicocomarts3098]

@1:15 "that's like 6 inches, Dan. That is huge!"

[@christosl467]

If you like to make the results more scientific you must test the long stem with a small bike and the short stem with a larger bike. And if you want to be precise test these things whilst your angles of the hips and shoulders stay the same at every testing

[@lillebltsbroen]

Precisely. The notion that there is much 'science' in these vidoes is - well, not quite true, to be polite.

[@bradcomis1066]

This video is really great! please more content like this exploring how bikes work!

[@Tangsters]

Thanks guys for this info. Always love the comedy!

[@Slogfester]

Good video. Slightly off topic, but concerning descending. THE best (by a country mile) handling road bike I have ever descended on is the Trek Domane SLR with 28 mm tyres. The decoupler thingy on the seat tube effectively provides damping for the rear end. Rails and sticks to the road like glue. All the test rides and reviews understandably focus on its handling of cobbles, but it seems no one ever went downhill on one.

[@smalerider1727]

70mm stem, 77mm reach handlebars, and 510 top tube. Definitely twitches, but it's what I ride so I'm used to it.

[@TheBonsaiZone]

If you put a scale under each wheel and measure the weight balance, you will find that a longer stem and moving the seat right forward will give an almost perfect 50/50 weight balance between the two wheels. This helps with the rolling resistance of the tires and helps the bike handle better in criteriums. I used to slide my bike sideways around the corners and bounce it lightly off the curb to get around faster!

[@rizkiyoist]

If you noticed, the bottom bracket of the bike is closer to the rear wheel than the front, effectively giving you more rear weight bias. Having 50-50 weight balance means you're putting quite some weight on the handlebar, and is actually not ideal for two wheels (unlike cars) on corners. On a bike you can often get away with rear wheel slipping slightly and then regain control, but usually not front wheel slip. Keeping a slight rear weight bias is better in corners.

[@DJWolves97]

Rizki Hadiaturrasyid Well if it is 50/50 weight distribution, then both tires with lose traction at the same time given no external factors (hitting rocks, twigs, etc)

[@kradtevitz5712]

Nigel, if you want the best weight balance standing still or going at constant speed, that's the way to go. However, the moment you need the grip from you tires the most is at corner entry or mid corner. You will be decelerating from braking and turning, throwing your weight forward, putting more weight on the front wheel. Therefore, I agree with Rizki, although for a different reason, to set up your center of gravity slightly to the rear. This is less ideal for corner exit, but at higher gears we are not able to accelerate enough to make the wheels spin or put the weight balance that much backwards, so it's better to optimize the weight balance for corner entry. I do think this video should have mentioned the change of weight balance with different stem lengths.

[@TheBonsaiZone]

@@kradtevitz5712 Awesome Krad, yes balance is everything when flying through the last corner in first place!

[@earthman4222]

I have a flatbar specialized city bike and I am older. Comfort is most important to me, so I put on a shorter stem with a pivot adjustment with degree marks. Boy was that a mistake. Super twitchy and not all that comfortable. I have hills where I live and I could not let it go downhill without the bike feeling like it had a frame made of gummy bears. I went back to the original....and I felt like it was on rails.

[@Kris_Strebel]

The main reason MTBs have a shorter stem now is because the frames are designed around it, with much longer reach than a road bike. It is more about centering weight between the wheels and having balanced grip. The width of common MTB handlebars is ~780mm, and a road bar pretty much maxes out at 440mm. So the stability comes from a wide bar, not a long stem.

[@connornorberg4402]

It's funny how what you're used to can have such an impact on what feels right and absolutely wrong to you. I'm personally a mountain biker (essentially no stem length on my trail bike) and the longer stem on my fixie feels sluggish and front heavy. Definitely gives me a feeling of impending doom on occasion but I still love that bike for commuting and whipping around the city.

[@slimjimmypage]

An important distinction between road bikes and mountain bikes when it comes to stem length is that mountain bikes are built with longer front ends to maintain proper reach even with those little 35mm guys and to keep weight further behind the front axle.

[@standandeliver8376]

Can't believe I've only just seen this. I used to have a flipped 80 or 90mm (can't quite remember) on my winter bike. The idea being a more upright riding position. On steep fast downhills the front would oscillate uncontrollably and get worse if I braked (a tankslapper in motorbiking circles). Very scary indeed!

[@treyquattro]

"... would things not be better with an 8?" "Oof."

[@normanzielke6108]

Short MTB stems are usually combined with humongous handlebars to maintain balance. So it had been better when you had paired the 80mm stem with a wider bar.

[@dubwb2217]

At 1:03 Dan explains what I’ve been wondering for some time. How it is that the pro’s are riding with seat posts jacked up to ridiculous lengths while their body dimensions haven’t changed all that much. Smaller frames! Of course, but how could that possibly be more comfortable vs the frame size they should be riding and normal seat post lengths? What we won’t do in the name of aerodynamics I suppose.

[@Arthur-ns4yh]

I'm personnaly coming back from injury, broken shoulder after a nasty crash. I recently started to ride my bike again, and since my arms stayed inactive during 3 months I found that I felt really bad on my bike, as if it was 2 sizes too big for me. Indeed I lost a lot of flexibility. I then immediatly swap my 110 stem to a 80 mm and I have to admit that my bike feels much more twitchy and, well, much safer on descent. I first thought it would be provisory but it might stay that way a bit longer than expected.

[@GuyRWood]

I can feel the difference. My winter bike has a 100mm stem and feels twitchier that my summer bike. My summer bike a 120mm stem and has a much more relaxed feeling but doesn't feel as stable doing slow, tight turns in the road like when you're turning around.

[@tonypowers123]

Finally. (For me). Simon, Simon, Simon 🙏 Hat off to you and God bless knowledge and experience ☝️ I’ll elaborate. At the end, Simon said something-perhaps at most important and significant factor. The Golden word here is- Feel. I absolutely agree 1000% that the bike INITIALLY should be ridden with The length stem intended by the manufacturer and design of the bike specifically to have the feel of the bike. Not “ride” quality as per speed and agility-feel. Whatever the intention of geometry and Design of the bike-that “little” thing called stem, makes a Huge difference on how the bike will feel. There is no rule of how it will affect you, but, it will affect first-Geometry, and correspondingly will affect you. Best explanation on what stem length does and how crucial is to feel quality of the bike!