I just got my first bike since college. It is a trek fx and I've had it a little over a month and I am just loving it. I have been using it mostly to run errands usually in the 6-8 miles range. Hubby and I have gone on longer rides on the weekends (10-15). I am overweight and I am having problems with my saddle post slipping down. Today, I went to the library and about halfway home i felt like my knees were coming up to my ears, LOL! I have tried tightening the clamp on the post as much as I can, but I can only tighten it so much and still be able to close the clamp. Any suggestions?