I might be missing something super obvious here but here goes…

Is there anything massively different between the Shimano M7000 single and double cranksets apart from the obvious (1x vs 2x)?

Would there be anything stopping me form getting the 2x set and running it with the M7000 1x rings if I wanted or is there some weirdness with the bolt positions etc?

Pondering getting the double for flexibility, even if it’s gonna be run as a 1x for the near future on a single speed setup.

I have an m8000 single chainset but it still has unused holes for an extra chainring, so I’m pretty sure the actual chainset is the same for either single or double set ups.

It’s the same casting – holes and all.

I was looking at a similar question from the point of an M675 10sp double.

Unless Shimano have found a way to fold space based on context, the crank is either optimised for single or double.

If it shifts acceptably in double configuration, I’d suggest that’s what it’s optimised for. It can’t possibly do both well without a lot of spacers.

If you want a crank that has options (was going to say ‘flexible’ but that’s got other connotations) I’d buy from a manufacturer that copes with the problem through a modular direct mount system with optional spiders. There are several.

The alternative viewpoint is that the whole chainline issue has been blown out of proportion and is much less sensitive to a few mm of variation than many folk would have you believe.

I have M8000 cranks on two bikes – one is 2x, one is 1x.

I bought the m7000 ‘single’ chainsets and the arms are the same as the double (have granny ring mounts). The only difference is which ring combination it is supplied with.

I have used several double or triple chainsets as a single ring setup for the last 14years and never had any chainline issues

I assume it’s the same as m8000 which uses the same cranks for 1x and 2x and yes, the chainline is rubbish for 1x. The chainring is aligned with 8th gear on the cassette which means crossing 7 gears to get to first. See this thread

The chain line is corrected by offset in the single ring. IME it’s worth spacing it in further still with chainring spacers (I used 3mm) if there is room. Some chainstay profiles won’t allow it though.

Thanks for all the answers everyone – that’s better news than I was expecting!

The chain line is corrected by offset in the single ring.

Really? I don’t see much offset in my single ring but I’ve not seen a 2x ring in the flesh to compare.