Replaced Ultegra 9-spd. STI with D-A 7700 STI; drivetrain now skips.
I wore out the Ultegra STI shifters on a road bike built up with Ultegra 9-speed. So I bought a brand new pair of Dura Ace 7700 9-speed STI levers cheap from ICYCLES. I installed them on the bike the same way I've installed several Ultegra levers over the years. I kept the Ultegra derailers.
Adjusting the rear shifting was hard. I've never had trouble doing it before. I've got it working, but the shift from the 3rd to 4th cog is still hard. The 3rd and 4th cog are also skipping under hard pedaling.
I replaced the chain and the cassette (both with SRAM parts) and the situation is no better.
What am I doing wrong? Is an Ultegra 6500 rear derailer incompatible with DA 7700 shifters?