I have a Marinoni Sportivo with a 9-speed drivetrain. I use Shimano 105 brifters with a Shadow XT rear derailleur, 105 front derailleur and a 52-42-30 crankset. My current wheels (Mavic XP-11 / Shimano RSX hubs) have a 11-34 SRAM cassette.
I am getting new wheels (Velocity Fusion / DT Swiss 240 hubs). I have an old Ultegra 12-27 cassette in my bin. Can I used the 12-27 cassette on the new wheels interchangeably with the current wheels?
I have a Shimano Flightdeck, which would of course need to be re-programmed but would I need to change anything else between wheel swaps?
I am also considering replacing the 30 tooth chainring with a 26 tooth, so that I can get close to the same gearing with a smaller cassette? Any reason why that won't work?