I agree with Mr Fietsbob, a Thudbuster ST (short throw) seat post works very well for me on paved roads. The LT (long throw) is for gravel and trail riding, especially if you are on a rigid frame (or if you're riding a hardtail and your butt complains). A carbon post helps somewhat but nothing like the Thudbuster. And both the LT and ST maintain the seat-to-pedal distance during the compression.