I just swapped the Suntour suspension fork on my Trek 3500 Disc for a carbon one. According to my fish scale, I shaved 5.10 lbs. The geometry changed a bit, but it feels for the better. It now feels more like my flat bar Cx which has a carbon fork. Should have done it a long time ago. My goal is to get rid of all of the steel on this thing. I think the next thing will be a XT Hollow-Tech crank. Eventually making it a 2x10.
Before:
After:
