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Discussion Starter · #1 ·
What’s everyone’s thoughts on a good sized stem length for a downcountry/trail bike??

I know it’s personal preference I respect to geo and bike fit bit what’s everyone’s thoughts on an ideal length?

Riding XC with a 90mm stem and going back to a 40mm stem is a strange feeling. Both bikes are of similar geo so would a compromise of a 60mm stem seem adequate or will this affect the handling too much do you think?

The way I see it is I’m used to XC so a shorter stem will still give a trail feel even if it’s longer than what’s normal.

Looking forward to everyone’s opinion!!
 

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Discussion Starter · #3 ·
Sorry should have written it better.
Got a new 120mm trail bike which comes with a 40mm stem.

Xc is what I’m used to with a 90mm stem.

Trail bike feels weird...will a 60-70mm stem be too long for a trail bike?
 

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Oh gotcha! Hmm, I don't think anyone but you (and maybe a trained bike fitter) could say what's "right" or "too long." Certainly nothing wrong with a 60-70mm stem if that's what feels good to your particular body on your particular bike. Plus, stems are cheap and easy to change so go nuts experimenting.

But also how long have you had the bike? It does seem natural that it would take a little while to get used to the new geometry, fit, riding position, etc., so you may find that you end up liking the short stem eventually. Only time (and more experimenting) will tell.
 

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Aim for between 40-55mm stem length based on fit and comfort.

Those long stems weren't such a problem when bars were super narrow but with wide bars and a long stem you get a really wide and awkward steering ark. It's like steering one of those little motor boats with the stick used to turn the motor. The longer stem is like a longer stick requiring larger and larger swings as the stick becomes longer.
 

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Aim for between 40-55mm stem length based on fit and comfort.

Those long stems weren't such a problem when bars were super narrow but with wide bars and a long stem you get a really wide and awkward steering ark. It's like steering one of those little motor boats with the stick used to turn the motor. The longer stem is like a longer stick requiring larger and larger swings as the stick becomes longer.
Totally agree! I couldn't stand the longer stem and wider bar combination. I had a 800mm / 60mm Bar/Stem, and to me, the steering felt slow and odd, with a lot of movement to do just a little turning. That might be good to slow down fast steering response and allow for some precision on downhill bikes, but didn't make me happy on my general purpose trail bike. I settled for a moderate bar (760mm) and short stem (35mm). It just felt better to me.

Outside of competition, bar and stem length are a personal-fit thing. Run what makes you more comfortable and confident. After all, what's the point to pleasure riding if you hate the ride?
 

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50 for my DC bikes which is what most DC bike maker specs their bikes with. They have slacker HAs and have longer front centers and reach compared to traditional XC bikes. And your weight is generally a bit further back regardless of stem choice. I like being able to load the front wheel and it’s harder to do that with a short stem.

I’m a regular average sized person though so I fit most bikes in my preferred size without making dramatic changes. I know taller people are more likely to use longer stems for ergonomic purposes and short people might use shorter stems to fit their bikes better.

+\- 10mm of stem length specced by the manufacturer on any given bike is a good starting point. Geometry for the most part is pretty optimized these days. Going from a 50mm to a 90mm stem may cause undesired handling changes. Conversely, going from a 50mm to a 30mm stem might seem rad at first, but can cause issues with loading the front wheel when cornering causing you to understeer while cornering. I guess the moral of the story here is don’t make any extreme changes to your bike.
 

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Trail bike feels weird...will a 60-70mm stem be too long for a trail bike?
No, it won't. Try the 70 and see what you think. I personally think it covers the ground well of not having the front wheel feel too vague, thus necessitating the need for more and more aggressive (read: heavier and heavier) front tires because the new geo has put us so far behind the front wheel, with shorter and shorter stems exacerbating that issue as well.

I came off hardtails with head angles too steep to ride what I was riding for years (yet I was still riding what I was riding just fine, I just never got the memo that what was fine before was now sacrilege;)) and was running a 100mm stem and 740 bars. My new 120 dualie has a 67 HA and I'm running an 80 with a 780 bar and Ikons and it feels pretty solid. I still have to weight the front if I really want to aggressively flick the front wheel over in certain turns but I will not put super chunky tires on 'downcountry' bike. Seems purpose defeating to me. To each their own though.
 

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Proper stem length is a matter of bike fit.
We don't 'choose' stem length - we get whichever stem length puts us in the correct riding position.
This^.

Usually, there is 20mm difference in reach between each frame size. Which typically means a person should only need to change +/- 10mm of stem from stock to dial in the fit. If you need more than 10mm of stem change to dial in the fit, then you probably should be on a different size frame.... but some people have their own preferences about upsizing/downsizing, or their body proportions are way off of typical.
 

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stem length bar width.. the comfortable fit requires a certain distance from shoulders to hands.

Wide bars, short stem is same fit as narrow bars, long stem. Pick bar width you like, then stem length follows.

wide bars short stem you’ve got more steering leverage. Turning is more stable.
Narrow bars long stem the front wheel turns faster, bike is twitchier.

I’m 6’1” and my shoulders like 780mm bars, I run a 50mm stem, it’s good for me on my bike.
 

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Proper stem length is a matter of bike fit.
We don't 'choose' stem length - we get whichever stem length puts us in the correct riding position.
=sParty
I disagree.
If you are having to put a 90mm stem on your DC bike to fit well, you simply bought too small of a bike and trying to make up for it with an extra long stem is a fools game. Sell the frame and start over.

Sent from my SM-G715A using Tapatalk
 

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I disagree.
If you are having to put a 90mm stem on your DC bike to fit well, you simply bought too small of a bike and trying to make up for it with an extra long stem is a fools game. Sell the frame and start over.

Sent from my SM-G715A using Tapatalk
If I size up, stack goes up, too.

Literally no one makes a bike with stack low enough with an ideal reach. Thus, ~445mm reach and 70-80mm stem.

For reference, I'm 5'5", 31.5" inseam.

Sent from my iPhone using Tapatalk
 

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Proper stem length is a matter of bike fit.
We don't 'choose' stem length - we get whichever stem length puts us in the correct riding position.
=sParty
Except, the correct riding position is different for different purposes.

If I am attacking steep trails I want those bars higher and further back, but that same position will make it harder to find front end bite on lower grade trails. And that same position that allows me to attack steep trails is not comfortable for big rides. Mountain biking is all about compromise, DH performance, climbing performance, and comfort are often in conflict. Stem length and rise is one of the easiest ways we have to tweak any of these.

Personally I have 3 three stems and two bars that I will swap out. My default is a 0 degree rise 60mm stem on a flat 720mm bar, I will swap in a -17 stem for big pedalling days. For more aggressive riding I have a 50mm stem on a small rise 740mm width bar. These swaps change the feel of the bike dramatically and even require a bit of suspension tuning to rebalance the bike.

For the OP, generally on a short travel trail bike stems are 40-70mm. If you are finding a 70mm is too short you are probably on a bike that is a bit small for you.
 

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If I size up, stack goes up, too.

Literally no one makes a bike with stack low enough with an ideal reach. Thus, ~445mm reach and 70-80mm stem.

For reference, I'm 5'5", 31.5" inseam.

Sent from my iPhone using Tapatalk
165mm cranks are amazing for those of us with short legs. All of sudden we almost fit 29ers.
 

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I disagree.
If you are having to put a 90mm stem on your DC bike to fit well, you simply bought too small of a bike and trying to make up for it with an extra long stem is a fools game. Sell the frame and start over.

Sent from my SM-G715A using Tapatalk
Uh no, incorrect. He isnt talking about putting a 90mm stem on his 'downcountry' bike, he was saying that his old xc bike had a 90 (which is completely normal), and whether or not he's ok to run a 60 to 70 vs a 40 to 50 etc on his new short travel. Which yes, yes he is. Some of us have been riding for many years and don't need to subscribe to the 'shorter is better and if it isn't you just don't fit in' mantra.
 
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