I have a 2010 Fuel Ex 8 purchased new in May. I continually have problems with the seatpost slipping down as I ride. In a 2 hour ride I'll have to raise it 2-3 times. More so if it's descending and technical. I end up riding for a ways in a bad position before I realize it's too low or before I take the time to stop and raise the seatpost again. Not acceptable if you are in a race. The bike has the stock seatpost and QR. I have tried chalk and grease without much luck. I've read of other solutions such as shimming, trying a new seatpost, and a new QR. Point is I don't think I should have to spend time and money on this considering it's a relatively new and stock bike. Should this be a warranty issue?? I have not contacted Trek yet. Any ideas.