10 speed crank running 9 speed chains?

[tzeonn]

Can a 10 speed crank run a 9 speed chain? The crank in qn is a m985 double with an xtr 9 speed chain. I also notice some protrudding links on the back of the big chain ring, anyone knows what this is for?

Thanks!

[yourdaguy]

It will work but not that well. Those protrudy things are called pinns. The help lift the chain from the little to the big ring when you shift. The too wide 9 speed chain will tend to catch on those pins when you are cross chaining.

[mattr]

I've been running it on several bikes (three road, two mtb) for a while (several years on the road bikes), with no issues.

Works perfectly, no noticeable difference in the cross chaining side of things either, still can't get the two top sprockets (12/13) from the small chainring on the road bike, same as with a full 9 speed set up.
Mountain bike's a bit different as i went triple 9 speed to a double 10 speed chainset. But i get the same loss of gears (11/12) as on my road bike. But all the gears i can't get, i a) wouldn't use and b) are duplicates anyway.

[tzeonn]

Thanks guys for the info about the protruding metal portion as pins, and no issues running with 9 speed cassettes

btw mattr, u mean u cant shift to the smallest rear cogs while on 10 speed chainset and 9speed chain/cassette?

[mattr]

Correct.
But then, you usually can't use those gears running an all 9 speed system either.
I have found on the MTB that its the big-big combinations that are "needed", rather than the little-little. And it'll go in to them without any complaints.