I just had a new chain put on my MTB. Everything is fine except under load (hard pedaling) the the chain ghost shifts on the rear cassette. It actually seems to not actually shift but more accurately just try to shift and then fall back on the proper sprocket.
I tried to loosen the rear cable on my ride this morning, but got no luck. I intend to play with it more tonight when i have time. What should i check? Why did the new chain make it do this?
BTW, the bike shifts fine in the stand. LBS adjusted shifting at time of chain replacement. I can take it back to them and will if i can't figure it out. Thanks.