I have a road bike, Shimano 105, 3 chainrings, 10 cogs. Today I replaced my chain (with a 105 10 speed Shimano chain, old chain had about 6K miles) and did some other minor maintenance, including removing/cleaning the rear derailleur pulleys.
Everything's great, except on the largest chainring and cog, where the chain pops off the tension (lower) pulley on the rear derailleur when I pedal. Looks like the chain is too low, and too far out (away from the bike) for the pulley to accept.
Anyone have any ideas? Might my new chain be too long or too short? Thanks so much.