9 spd on 10 speed crankset

Try a 10-speed chain. It will work perfectly on the cassette and may
work well with your front derailleur and front shifter.

L D Lide

damyth said:

I have a Shimano Ultegra FC-6600 (10 spd) crankset, and recently
downgraded to a 9 spd cassette and chain, and brifters to keep all my
bikes uniformly 9 spd. The chain happens to be an SRAM PG-970.

I've noticed that the chain catches on the (inner) ramps of the large
chain ring when I'm in the small chain ring and the two smallest cogs
on the cassette. Yes, I try not to cross shift but the second
smallest cog on the cassette happens to be optimal for me when I'm in
the small chain ring.

Are there chain ring shims/washers that I can use to give a little
greater spacing between the chain rings to alleviate this problem?
Any other suggestions on how to solve this problem (short of "get a 9
spd crankset" or "don't use those gears"😉? It's hard for me to
believe when it comes to Shimano crank sets, there is such little
tolerance between 6.14 vs. 6.6 mm, the widths of 10 and 9 spd chains
respectively.

Thanks!

Well, there is. Shims are not a good idea, like starting out in a
manual transmission car in 3rd instead of 1st, don't use the smallest
2 cogs when in the small, ring or get a '8s' or 9s crank. Not really a
'problem', when shifting up 2-3 cogs and into the big ring with those
really convenient lever mounted shifters are right there.