Originally Posted by
vasuvius
The drive train on my bike is Ultegra 6600 with a 12-25 Ultegra 6600 cassette
Recently I replaced the chain with an Ultegra CN-6701 and it has been working fine for 500+ miles.
I just bought a new set of wheels and got a new cassette so that I could use the old wheel and cassette for the trainer.
I got an Ultegra CS-6700 - same spec as before : 12-25
The spacers are exactly the same and visually the space between the cogs look exactly the same as the old 6600 cassette.
But when I put the new wheel on bike, there are a couple shifting hitches...
I recently went from 5600 to 5700. One thing that could cause an issue is that the chains have an inside and an outside. If I remember correctly, the plates with the Shimano go on the outside. The cassettes and chainrings are supposed to work with the new shapes. The shapes are definitely different. I adjust my derailleurs whenever I change a chain and recommend that, too.