Finally went out for an outdoor ride a few days ago (I ride mostly indoors) and after just 40 mins. of riding on semi-rough roads, I found that my seatpost had gone down 2 centimeters! Pisses me off! How should I fix this? I'm thinking I can put some gnurling (sp?) on the post to help the collar get a better grip. Some have suggested I put a shim, but I do not know how I can do that. Any suggestions or tips? BTW, I am so happy! All that work on the trainer has made me WAY faster than I was before!