[Closed] Converting M785 XT 2x crank to 1x

Should be fine. Normally with the shimano double cranks you'd need to space the chainring in by 2.5mm to correst the chainline. If you use a 30 tooth ring, they have the spacers built in to keep the chain from fouling on the spider arms so they'd just fit straight on as they are.

Bump for the evening crowd.

Thanks andy - anyone agree?
Any pics of your setup appreciated 😉

I agree.
Also FYI, absolute black do a 32t oval chainring with the same built in spacers. I'm running one on my solaris and quite like it.

Double crank
Chainring on outer tabs, spaced as above so the chain clears the arms
30t rings often have the spacers built in
Although I've had no problems with chainlink a 32t on double XTR or XT cranks or middle bolts of a triple FSA

Have you considered an oval 32t ring instead?

Eh?

Surely buying a triple would be a better idea than buying a double and then offsetting your cranks.

I also agree. 32 round, and spacered on XT 2x M785

further reading if you're bored. http://singletrackmag.com/forum/topic/33t-ring-on-xt-double-anyone-run-this

There are some links in there that will help satisfy you about the issues and remedies, though.

But as dirtydog says, if your only interest is buying one to use as 1x, and no interest in going 2x at some other point, then you'd be better off with the triple.

I can get the 2x at a good price in A1 condition - if I need to use a spacer (and there's even disagreement within this thread) I don't really see the big deal...

no big deal.

no disagreement really, either. Some rings have a spacer built in for just this reason, some don't. If the ring you buy doesn't have an integral spacer, you'll need to add your own.

everything you need to know:

If your running a 30t you will need to space it out anyway as the ring diameter is slightly smaller than the crank spider so the chain will clash unless it's spacered out this is why most manufacturers 30t narrow wide rings have tabs attached whereas their 32t and above don't (Superstar, Race Face and Works Components spring to mind as examples)

Get whichever crank is cheapest 2x or 3x you shouldn't have a problem with either
3x probably has advantage you could fit a bash to the outer tabs if you wanted but that's about it

Have you considered an oval 32t ring instead?

Another thing....I've been used to 175mm cranks for years.
These are 180mm....reason not to get them or worrying over nothing?
Left knee can get iffy on long rides - due to Achilles injury of all things!

I moved the DS BB spacer across to the NDS, and used 2mm spacers for the chainring (although now on a 30t with the spacers and threads built in).

I've found that knee problems were helped a little by going from 175 to 170.

165s seem to be fine too (bought some cheap Zee cranks to try on the 1x cross bike as an experiment - seen no reason to take them off). Personally, I'd pass on 180s. I'm 5'11.

You might be fine though, especially if you're tall. But if your knee problems are due to acheilles problems, I'd guess it won't be helpful to be on longer cranks, your feet will be further apart when the pedals are level, so the achilles on the rear foot will be more stretched.

Also, you'll be more prone to pedal strike on longer cranks, but you don't ride rocky trails and it never happens now with your 175s, that probably won't be an issue on the 180s.

180mm cranks and iffy knees, I wouldn't, have a look for other cranks. the weight and stiffness variations of a crank arm isn't that big, where the posh ones differ is the rings and you won't have the OEM ones on anyway...

After much consideration I've decided that as lovely as the cranks were, 180mm and the possibility of worse knees is a non-starter 🙁
The search for 175mm continues...

170s in the classifieds. You probably won't notice the difference from 175mm, and it might help your knees.

http://singletrackmag.com/forum/topic/top-end-stuff-that-needs-to-go