I’ve got a 2008 shimano slx crankset and i need new middle (32) and outer (44) rings.

Even wiggle’s limited selection has got me confused. Although I have managed to buy the right ones in the past, I think this may have been luck rather than judgement.

Can somebody either tell me which ones are compatible, or please point me in the direction of some sort of compatibility table?

I know that I should know this stuff already, but any help would be appreciated.

Thanks.

4×104, which is 4 bolt holes, 104mm between centres.

Is that the only compatibility issue?

If so, thanks.

And I feel a proper numpty(!)

No, some 4 bolt rings of same pcd have a different radius cut into them inside of the bolt holes. Shimano have also made rounded tabs on some of the newer middle rings that look completely different to the old style tabs that we see on just about every ring out there.

This inner radius is hard to tell by the eye,it’s approx 3-4mm smaller on some rings regardless of the same pcd. Measurement or trial and error will be the way to tell the difference if you aren’t quite sure which ring you have bought/stumbled upon/been given ;O)

Compatibility issues can be resolved with a file.