Originally Posted by Carbonfiberboy

Seatpost clamped to the forward end of the rails is not good. Need more setback on that seatpost. You can measure on the saddle rails to see how much setback you need to be somewhere in the middle of the rails. You don't have to have perfect balance, just good enough that your hands and arms don't get tired.

Clamping near the end of the rails can cause the rail attachment to fail. Very embarrassing and a huge PITA during the ride.