Hi, I lurk, and don't usually post, but have a problem I can't seem to solve. When I ride, I keep moving my behind farther back on the saddle until it's extended somewhat off the back of the saddle. That would be ok, except then I get a lot of chaffing. The obvious solution would be to raise the saddle, and that's the problem. If I raise the saddle where I feel like it needs to be, my feet don't touch the ground, not even on tiptoes. Any ideas would be appreciated because this is keeping me from enjoying my bike.