Chainring compatibility-double rings on a triple crank

bails87

I've got an m660 SLX crankset, currently set up as a 2x9 double. I'll be changing to a 2x10 setup at some point in the near future. I've got all the bits I need apart from chainrings, obviously it's cheaper to get rings then a replacement slx crank set.

When I do change, can I use 10 speed chainrings intended for one of the shimano doubles? Is there any issue with putting double rings on a triple crank, or is it just a case of getting anything with the same BCD and the right number of speeds.

Would fitting a bash ring make any difference?

Cheers

The Rookie

Nominally 9 and 10 are different, in reality no-one has ever been able to really define what they are, many people are running 10 speed rear with 9 front (cranks and/or rings) without issue. Yes you can fit double rings to a treble, either with a bash or without, you just need the right ring bolts for the assembled thickness.

bails87

Cheers, just wanted to check there wasn't anything odd about them.

Yeah, I'm currently running an 8 speed chainrings and a 10 speed front mech with no issues. Just hope I can find some rings that aren't extortionate!

The Rookie

What sizes are you planning? I have an Shimano SG-X 28T inner surplus to requirements...

njee20

As above, in reality they're similar enough that there's no difference, I'd just keep what you have unless you want drastically different ratios.

bails87

Currently on 24/38 which I'm happy to stick with. I doubt the inner is very worn and the middle/outer is steel so that'll last forever, it was the '10 speed chain on an 8 speed ring' that was making me think I'd have to get a new ring. If it'll work then I'll happily leave it.

The Rookie

It'll work fine, leave it!