The chain on my bike just recently started hopping from the middle ring to the small ring then off onto the BB when I pedel backwards which I tend to do when I am at a stop and start up again. I looked at the bike in the stand and check for things like adjustment of the front deraileur, frozen rear deraileur cog, frozen chain link, missaligned rear derailuer due to a bent rear dropout, etc and could not detect anything wrong. I decided to replace the chain thinking that maybe it is twisted as I noticed that everytime the chain dropped off the front chain ring (it starts dropping off the chain ring when the chain is at the bottom of the ring) it was also dropping off the rear cog too (at the top of the cog). Anyone ever had a simliar problem? I will be test riding the bike tonight so I don't know yet if the new chain will solve the problem but I couldn't get the chain to drop when it was on the stand with the new chain....