I have been riding my new bike for about a week now and I am pretty sure I need a new stem. The bike is a 20" and the stem is a 110mm. When I am going fast/on any semi-technical questions I have no problems with my grip on the bars. But, when I am on long rides I keep finding myself naturally resting my hands on the grips right behind my fingers9dont know the name of that part of my hand). If I stay down were Im supposed to be my back starts to hurt after a while. I was thinking of moving to a 90mm stem so i am on the bars where I am supposed to be and more comfortable. Am I going to lose any handling characteristics by moving to a shorter stem? The frame fits me fine, but the stem is just a wee bit too long for my comfort on long rides. I am probably going to keep the same rise, but just make it shorter. Does this make sense?

Also, unfortunately, there are no stems at my work that I can just throw on and test out. There are plenty of stems, just nothing that will work with my bars(I beleive 31.8mm). Does it seem advisable to just order one up and try it out? I figure since im getting a new one Im going to upgrade as well

Thanks for any info you may be able to enlighten me with.

Go to another shop that DOES have something you can try. You may not notice a huge difference between 110mm and 90mm. You may wanna pony up for a custom 88mm stem.

my back hurts at the start of each season, after a few rides the muscles come back and I feel better. I tend to mess with stems and handle bars quite a bit at this time, but I find that I am wasting time (and money), nothing like getting some miles in to improve back strength and then maybe look for new stems.

I changed stems on my road bike from I think a 110 to a 90 and it made an incredible difference. I would say find one and try it out. Sometimes that 10 or 20mm can be pretty noticeable.

There's no substitute for doing what everybody else has done... keep buying stems until you find one that works for you. I know I have a nice little collection of stems I will probably never use again :-)

It's not what some fitting at a bikeshop will do, it's what feels right for you. You might even want to change stems again later on as you get fitter or your goals change.

Yesterday I rode some fast, tight, and semi-technical single track. My back was fine through out the whole ride, but now I notice on this terrain that I am riding sort of sketchy. For example, my front wheel is all over the place on the tight turns. I know its probably just me not being used to the bike or the riding(havent riden single track in those conditions in years), combined with the clipless pedals which are new for me. I fell a couple times, for the first time on these pedals, only once was my fault though(the second time a tree branch snagged my pack and pulled me down) So, I think I am going to just try to keep this stem for a while and see how everything pans out. Ill give it a few more weeks and see what happens. It seems if I change the stem it could significantly change how I ride the bike, and Im not even used to this set-up yet. So I wait.

I would give it some time.

Though I am newer around here, I am a roadie with some experience. Same thing over there . . . your body will fight you in a new position doing new things. I do not care who fits someone to a MTB, even with every custom part, the new rider is going to have A) hands that hurt and B) neck or back pain. They are also going to be uneasy on single track trails. They front end might be squirrly. They may go down a few times.

IMHO making changes now is not the idea thing. It might cost you money and it will only add to the doubt that some part is the reason you are not riding faster through the trails. Give it a handful of tries and then start to look at adjustments.

Just my $.02. After 6 or 7 rides this season so far (just got my MTB this winter) it feels like night and day since the first ride.

i prefer the short stem handling.. I went from a 100mm to a 75 and I like it better, My bike probably has a top tube too long for me though.