Bicycle Mechanics - 32 tooth cassette to 34

Hello Mechanics,

I recently upgraded my XTR cassette from 32 to 34 teeth. I added a link to my chain and everything shifts fine, but I sense I may be getting more chainslap than usual. I don't know if I'm imagining this or not as I wasn't sure if I should have added a link to begin with and think I may just be more aware of the chainslap now than before because of my new awareness.

So, is there a rule of thumb here regarding adding a link while adding teeth in your cassette? Any tips would be appreciated.

I doubt that the added link made enough difference in the RD idler tension to be a factor, but you should double check that your chain isn't too long by shifting to the small/small combination and seeing that the RD takes up all the slack.

Otherwise You're probably attuned to any difference and the chainslap is the same. With the chain on smaller sprockets the top loop is so close to the chainstay that chainslap is unavoidable. You can't solve it so use a decent chainstay protector either DIY or bought. If you don't like the noise, foamed neoprene like what's used to insulate pipes does a great job muffling it.

Shift into your little/little combination. If your bottom chain run doesn't go slack you're OK.

Thanks for the quick response. When my chain is in the small rear and granny front, the chain is about parallel to the ground as is the RD. The chain has no arc in it, so is this what you mean by being slack free? Thanks for the thoughts.

The chain has no arc in it, so is this what you mean by being slack free? .

Yes, as long as the RD cage isn't rotated back against the stop and the lower loop has any tension it's fine. If you wan to be absolutely sure, note the position of the idler cage, and lift the lower loop off the chainring and see if the RD can rotate back a bit more when you give it slack.

It sounds as if you're okay. It's possible that you are getting more chain slap than before (as you have one more chain link, which applies in all given gears except the 34t I guess) but this isn't fundamentally a problem if the derailer is still basically taking up the chain slap.
It's also possible, as mentioned, that you're simply more aware of the potential problem, standard placebo or confirmation-bias stuff.

Thanks for all the tips. FBinNY, your detailed explanation really helped and I think my chain length is A-Ok.

Best, Paule

Thanks for all the tips. FBinNY, your detailed explanation really helped and I think my chain length is A-Ok.

Best, Paule:)

If it bugged me, I might try tightening the rear derailleur pivot spring one click. My old Suntour VXGT comes apart at the pivot, and the spring can be tightened in small increments. My "modern" Shimano Acera doesn't.

Or I'd just ignore it. Depends on whether it actually seemed to be causing real problems, like shifting troubles, or chain-drop.