[shark36]

I would like to change the stem at my AM bike, to bring the bar closer to me (I have a feeling, that the frame is a little to big; but really a little to big for me). My option is to change the actuall stem of 11 cm and 6 deg., for a 7 cm and 35 deg. stem. Than if it will be still not enough, I would put instead 40mm raisebar, 50mm raisebar.

I read a lot of articles regarding stem change ( including http://www.leelikesbikes.com/stem-lengthrise-for-a-trail-bike.html ). But still in some articles I saw, that a change around 4 cm can brake/change/spoil, the geometry of the bike. Specially the stability of the bike also at DH.

Experts: Is it truth, that such a change can have an impact on stability of the bike and brake a geometry? Or am I safe to make a change in order to bring the bar closer to me....

 

[crisillo]

the geometry remains the same...what you are changing is your position on the bike and a bit the weight distribution... as well as the responsiveness of the steering....

it should be safe to make the change as long as you can ride comfortably, the rest you can make up by moving your weight around (for example you might need to push the front down a bit on climbs)

 

[jeffus]

Perhaps take your bike to the LBS and ask them to help in your choice of stem, they may have a few options to fit and see how you feel on the bike before you buy one of them, stem only takes a couple of minutes to change, change one thing at a time, the stem is a good place to start.

 

[kapusta]

I would like to change the stem at my AM bike, to bring the bar closer to me (I have a feeling, that the frame is a little to big; but really a little to big for me). My option is to change the actuall stem of 11 cm and 6 deg., for a 7 cm and 35 deg. stem. Than if it will be still not enough, I would put instead 40mm raisebar, 50mm raisebar.

I read a lot of articles regarding stem change ( including http://www.leelikesbikes.com/stem-lengthrise-for-a-trail-bike.html ). But still in some articles I saw, that a change around 4 cm can brake/change/spoil, the geometry of the bike. Specially the stability of the bike also at DH.

Experts: Is it truth, that such a change can have an impact on stability of the bike and brake a geometry? Or am I safe to make a change in order to bring the bar closer to me....

Changing the reach 40mm is a pretty big change in the way the bike feels and handles, but I think to say that it "ruins" the geometry is not necessarily true. It may help your situation.

One thing to keep in mind is that with such a high rise (35 deg), that 70mm brings the bar more than 40mm closer to you. Check out this stem chart:

http://www.habcycles.com/fitting.html

Remember that you need to add your head tube angle (measured from horizontal, so for a 70 degree head angle, add 20 degrees to all stem angles, 69 add 21, etc)

You'll see that you are actually shortening the reach by about 60mm. That is a lot. I would try a smaller change. I find that even 20mm makes a difference. Just find some cheap stems to play around with until you find what works best. There is nothing wrong with trying something to see if it works.

 

[EnglishT]

Wouldnt change the stem length by 40mm... even if the handling is seriously slow, and you prefer it seriously quick, that could still be alot.


Might be a better idea to try changing it by 10 or 20, changing the bars, and moving the saddle position forward (or going to an inline post).

 

[shark36]

I made a change, it was to much For downhill it was OK (even great), but for uphill, I had pain in my back already after 30 minutes. Tried the change 3 days on the row, but the result was the same :nono: Knowing that I spet at least 75% of my time uphill and the rest downhill it was not acceptable.

So I went for the "middle" solution and the one, that was recomended by the majority of the members here - 9 cm and 12 degres. Now it is :thumbsup:

 

[LCW]

.

...