I have had a problem with these seats. I have an old one on my time trial bike and it works fine. I had one on my Road frame and it was working fine for about six months, but now the rails flex out of the carbon shell and it sqeaks. It drives me nuts. I took it back to the local bike shop to send it back for warranty. The Local Bike shop gave me another one to ride in the meantime. After two rides the new one is squeaking. I have gained some weight, but not that much. I weigh 180 and I am 6'-2" tall .Is there an unknown weight limit on this particular seat? Has anybody had the same problems? I have now ordered a Serfas Aria. I have one on my track bike, and it is pretty stout. Let me know.