# How to calculate determined stem length?



## -=phelan=- (Nov 11, 2006)

I'm kinda of lost in determining how to buy a new stem pretty much. Any advice on stem length? Isn't it usually the shorter the stem the more quick you're able to turn the bike and the longer it is the better it is for long distance ride (more aero?) maybe more stability that way?


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## Speedub.Nate (Dec 31, 2003)

Mostly correct.

Shorter is faster steering and more upright while longer is slowing steering and more stretched out, when all else is relative.

But don't forget to factor in saddle position, top tube length and handlebar drop.

Saddle Position, relative to your cranks, is the "home" position. All else should be derived from there.

Ideally, Top Tube Length would be determined after everything else is set up, but that's not exactly practical unless you've really put some thought into a bike purchase. But if you're trying to make up for too short a TT, you've got to correct that with a longer stem, and vice versa.

Bar drop is important for power output, comfort, and position. You could take the same length stem, but change the bar height from level (with the saddle) to, say, -2.5", and the bike and your riding position would feel completely different. Doesn't really matter if you achieve this by flipping the stem, reducing spacers, switching to a flat bar from a riser, or any combination thereof... net result is where your grips end up relative to the saddle.

So given all that, are you trying to determine a stem length from scratch? Or is there something in particular you don't like about your current riding position?

To compare the reach and rise differences between different stem sizes, try this:


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## -=phelan=- (Nov 11, 2006)

^^ well i'm getting a little bit of a sore back when i'm riding for a duration of 2+hrs and that's never good. Isn't that usually a symptom that you're not upright enough? 

So what i've been thinking is getting a low riser bar to get that that slightly more upright position, but seeing how easton monkeylites are dirt cheap now (check the the best deal thread) i've been contemplating about changing over from my 31.8 stem to a 25.4 stem for the bar (it's that cheap)


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## Speedub.Nate (Dec 31, 2003)

Your back problem could be attributed to any number of things: reach, rise, medical, stretching, and I wouldn't even pretend to be even remotely qualified to offer a diagnosis.

But sure, if you're willing to experiment with cockpit setup, up or in are two options to try.


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## chinaman (Jun 8, 2007)

I had the same problem with a 110mm stem and just swapped it round for a 90mm and what a difference that makes ... i ride a XC hardtail.

The thing is previously on a different bike i was using a 100mm stem and it was fine and when i changed the frame, i thought i would try a 110mm ... hence the introduction of a sore back.

What stem size are you using now? What kind of riding do you do and what bike do you have?

Everybody is made differently and so will prefer different positions, trial and error is best.

_I will suggest you get stems of various sizes from ebay and that way you can sell them on for a smaller loss. My XC HT has gone through 2 stems and so has my FS._


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## -=phelan=- (Nov 11, 2006)

I've got a 06 stumpy HT and mainly ride XC trails. I believe the stock stem length is 100mm, will have to check, (unless someone knows on here?) I'm thinking of making a change over to a 90mm stem with a more upright position on a low riser bar vs that of the flatbar.


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