The only thing you might notice is that the 990 is lighter. The '05 950 that came on my Prophet shifted just fine but weighs about 450 grams. The '05 990 that I bought was about 150 grams lighter (about 5.5 ounces) and shifts about the same.
A forum community dedicated to Mountain Bike owners and enthusiasts. Come join the discussion about bike parts, components, deals, performance, modifications, classifieds, trails, troubleshooting, maintenance, and more!