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I currently run a 2x9 setup with bash and use my bail out granny enough to justify it.
If I were to go to m980 cranks is it possible to go triple option cranks and run it as a double like my current setup and then have the option of going single later using the middle ring?
At first the double trail option sounds obvious but if going single later the ring will be offset and I would prefer it in the middle of the drive line.
Would chainrings like the 33t Renthal etc fit to the middle position of a m980 triple crank or is is all funny sizes and offsets?
Hope my questions makes sense and thanks for any help. 
I'm running double and bash on mine, so yes it is possible. I went with the triple so that I could swap the big ring for a bash ring but mostly to keep my options open with the standard BCD. Currently 22/36 with an 11-32 cassette. Kind of prefer the 32 single ring and 11-34 cassette on my hardtail, but not ready to loose the granny on the full sus just yet (I think) handy when you are tired! Full sus is more weekends away, while Hardtail local 1-2 hr rides.
The triple is the one you want for 'normal' compatability.
You can pretty much run any combination you please with that.
I have a triple, which I use as a 1x10 setup, with a full chainguide.
The double is an odd BCD.
The Race double is an 88mm BCD, not insurmountable, but more of a pain, I got a ti 36t ring from Experimental Prototype to fit. If you want more off the shelf parts then the triple makes more sense!
I like these answers. At one point I did have m970 xtr cranks and they were a little bit of a faff to run as double and I was worried the newer XTR would kill off options.
The above sounds good.
AFAIK the only funny offset is on the granny tabs, so I kept the original ring and flogged the middle and big rings in favour of a 36T XT ring and lightweight bash (BBG?). Tried an old granny ring from the parts bin and it would have needed spacing off (which seemed a faff considering replacement cost of M980 grannies is reasonable).
The Trail double 38/26 uses the same cranks (M980) as the triple version. However all the other doubles are different.
For what you want the Trail double sounds like the ticket. If you're interested I also just happen to have a set of new 175s for sale!
Cheers
Teapot
Cheers Teapot - I will be looking for 170mm.
Now I am properly confused. How does a double use the same cranks/web as a triple with same offset etc? 😕
Mr Plow: because the granny ring location remains the same. With a double the big ring runs on the inside of the outer spider and there's nothing on the outside. With a triple the middle and big ring run either side of the outer spider with a deeper chainring bolt backing nut
Hi,
Yeah,the trail double would be ideal.That's what I've been runnin with a single for a year.
Thanx,
Max