I think i remember reading that the 38t ring on the 38/24 crankset is different to the 38t ring on the 38/26 crankset.

I think it had something to do with the ramp profiling to enable the bigger jump in size between rings.

*edit*
Found the Shimano parts listing, there are two different 38t rings:
[url= http://techdocs.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/FC/EV-FC-M785-3165A_v1_m56577569830800932.pdf ]M785 Tech Doc[/url]

Silver or Black?

Madison don't appear to be listing it. If they were, it would be part # 1ML 2400

Yeah don't seem to have them. Might be worth emailing Madison.

Here's the [url= http://cycle.shimano-eu.com/media/techdocs/content/cycle/EV/bikecomponents/FC/EV-FC-M785-3165A_v1_m56577569830800932.pdf ]Tech Docs[/url]

Either way, I'm pretty sure that he'll need to replace his 38t ring as well.

mlucas666 - Member
Either way, I'm pretty sure that he'll need to replace his 38t ring as well.

POSTED 5 SECONDS AGO # REPORT-POST

+1
Your not going to get a mech that will work with a 24/38 rings without rubbing, 24/36 is about as wide as you can go.

madison list 1mm2400 chainring. for the m780 chain set. £19.99 and in stock. [u]might[/u] be compatible.

Thanks all, maybe I need to get fitter lol.....

Yeah, you'll need a matched pair of AM38 and AM24 chainrings for the smoothest shifting. The 38/24 M785 combination has only just come out, and I haven't seen anyone offering the chainrings separately yet - may have to wait a while. Could probably get away with the M780 24 ring in the meantime, or even the SLX M675 24 ring, but won't be as good shifting as the proper M785 24/38 matched set.

Your not going to get a mech that will work with a 24/38 rings without rubbing, 24/36 is about as wide as you can go.

Utter tosh - Shimano offer the 24/38 as a stock combination now in both SLX and XT, and it works perfectly with the their 2x10 mechs. Just like the old SLX M665 22/36 worked great with the same jump of 14T.