Advice on cassette/RD mismatch
Got a question for the bike mechanics among us. I have a CAAD12/Ultegra with the short-cage R8000 derailleur. I recently replaced the 11-30 cassette with an 11-32, which is beyond spec for the short-cage RD.
It shifts fine and runs quiet on the larger cogs including the 32T. However, when up-shifting to smaller cogs, the chain hesitates and sometimes skips over a gear. The chain is new (DA). The bike's been to my LBS and I believe they've adjusted the RD to be as good as it can be, but it's still not ideal.
My thinking is that I need to install the long-cage R8000 derailleur to truly fix this issue. It's not that much money (around $85). Here are my questions:
1) Is changing the RD a likely fix for the shifting problem?
2) Do I need to lengthen the chain to accommodate the larger RD? Shimano's instructions say to measure chain length without the RD in the path, so this implies the choice of RD has no effect on optimal chain length.
3) When adjusting the replacement RD, I'm familiar with how to adjust the limit screws, the "B" screw (for height) and the barrel adjuster. Are there any other special things I need to know?
Thank you.
Last edited by Robert A; 07-12-20 at 06:44 PM.