Im thinking of going from 100mm - 15` rise to 120mm - 6' rise. What type of changes will I see i.e. quicker steering, body positioning, etc??
The main change you will see on your bike is a 20mm longer stem on it.
You will experience a slightly diferent weight distribution towards the front of the bike, as the other post says more strech out position.
It would slow down the steering.and make it more difficult to control on the downhills... Obviously that`s what hapens in paper, but the real effect it has depends on your riding and the bike`s geometry.
I did that on my Kikapu.. switch from a 90mm stem to a 110mm. to avoid my front wheel from lifting. And since the kikapu has a very salck head angle it didnr affect me much on the downhills. But i noticed the slooooow steering effect.
Lesson of the month: Don`t run of a cliff on your Mountain Bike. It`s quite painful.
It will slow the steering and transfer you're weight bias towards the front. The latter can help going up but WILL HURT going down. If you're a pure XC climber type a longer stem will help but if you're into the DH the shorter stem is confidence inspiring.