I'm stumped. I took my bike to the LBS and they couldn't find a problem so maybe you folks can help.
My 9 speed Ultegra rear derailleur hesitates or doesn't shift when I'm shifting from cog 3 to 4, 4 to 5, 5 to 6, and sometimes 6 to 7. Same thing when going the other way. The cogs don't look worn. Happens on large and small chainring. This has been a problem for a few months.
I've cleaned and lubed the drivetrain but it doesn't help. I've adjusted the cable tension and tried turning the small barrel adjuster (1/4 turn increments) near the rear der.
The chain isn't stretched and has ~4000 miles on it.
The bike has ~11,000 miles.
Is the problem in the shifter?
Is it time to change the chain even though it isn't stretched?
Thanks for your help.