So been in the shed and found a old triple set of deore cranks, been asked to put a single chain ring on them for a bike build but, how do I work out what size chainring will fit e.g 104 or 96 ?
They did some triples with 30T middle rings to drop the gearing for 29” wheels to make closer to 32T on a 650b wheel. Not sure anyone ever thanked them for it.
They used 96mm BCD but in a symmetrical pattern as opposed to 104mm, or the later 1x/2x offset 96mm BCDs.
If your Deore crank is FC-M612, then that’s what you have and you can use one of these to go 1x :-