My last two time trials my rear racing wheel (Rolf Vector Pro with a wheelbuilder cover) has been acting up. It seems as though the cassette is tight? grabby? won't spin freely? I know the Rolf Vector Pro is notorious for being loud when spinning but is it also known for having a tight free hub body? The rear derailleaur (when coasting) slaps up and down due to the cassette not spinning freely. I'm afraid something is going to break. I took the wheel off and compared it to my Shimano R-550 training wheel. The cassette on the shimano spins much, much easier than the Rolf. Is there an easy fix to get the cassette spinning easier? This problem just started a week ago. Thanks alot.