BN shoes require a little forced abuse on them to "mate" them to the bell.....on a brand new set-up before you start reving the peanuts out of it......drop it on the ground...Hold it in place and rev it for a couple seconds....DONT let the tires move.....your basically looking to force slip the shoes to break them in....dont go overkill and do it over and over....once is enough and your set-up will thank you with a little longer life.....with composite's be careful...even a few seconds of 100% slip can damage them...so be quick about it on a comp/alum set-up...as glazing over the composite shoes is the last thing you want to happen.