my chain as been jumping lately but it seems as though only when im pedaling hard. at first it was doing it in almost every gear (11-32 t) then i noticed my chain was binding up in some of the joints so i replaced it. i just put on the new chain and now its only doing it in the 11t chain ring. could i have rounded off the teeth on the cassette from the chain jumping? or is my derailluer just not tunned in right? ive tried to look back at the cassette as it skips and it looks like its just popping straight off the top instead of trying to go up to the next ring. so i think the derailuer is fine. any thoughts?