10 speed chainrings with 9 speed chains?

I spoke to Shimano (Sydney) about a problem just like yours earlier this week.

A 10 speed FD and Chain (DA) will be needed. make sure the FD has a 16 tooth capacity.

nerdag said:

Was hoping that some of you would know the answer to this one...

I've just bought a cheap Truvativ Rouleur compact 50/36 to replace the worn 52/39 crank on a commuter bike. (I know I could have just replaced the rings, but, I was after a 34 or 36 so that I could use a 12-23 instead of a 12-25 - tighter gearing, since I don't use 52/12 when commuting anyway).

Problem is, the chainrings are marked as 10 speed only. I've read that this shouldn't be a barrier to using a 9 speed drivetrain on it, however, I've been having problems setting this one up properly.

Basically, when shifting from the small to the big ring, occasionally the chain will skate over the teeth (ie. without the teeth sitting between the rollers) for about half a turn, and then snaps into place. Doesn't happen going from big to small - I've not been able to get that to play up. Usually happens when I'm in the

No amount of FD adjustment has gotten it to work, so question is, am I dealing with a chainring/chain compatibility issue? Chainline (I think it's spot on)?

Or is it just a fiddly FD? (I'm using a well used and chain rubbed Dura Ace 9 FD, however, the part that makes contact with the chain on the compact cranks are not the worn parts of the cage).

Any help would be much appreciated!

Cheers,

n

Try an FSA 50T 110mm BCD chainring. It should work fine with the 9s chain. As gclark has aluded to in several posts the pick-up pins on some of the 10s rings don't work well with 9s chains. On some brands of chain rings, the 9s and 10s are pretty much interchangeable. I have used the same FSA chainring with both 10s and 9s chains with good performance and without the hang-up that you are seeing with that Truvativ.

might be that the regular frt der you have is not arched enough to follow the smaller 50t chainring. if that's the case the derailleur won't push up very hard since the tail of the derailleur will be (relatively) far away from the chainring. there are "compact crank" frt der's out there.

10s chainrings are simply a bit thinner but I haven't used a 9s chain with a 10s chainring (but I am running all 10s chains on 9s chainrings for two+ years without problems).

good luck