Am thinking about the XTR crankset (double) but the chainline is too small for my frame. Anyone used spacers to push it out a little? How far can it go? I’d probably need 3mm.

that should be fine, i used 2 spacers to push my chainset out when i went HTII single ring on my old lava dome

You could move a 2.5mm spacer from the left to the right if you have a 68mm BB shell, although it will mean your whole chainset is off centre.

If you have a 73mm BB shell, or pressfit, then there’s nothing you can do, there’s not enough spare axle to add additional spacers. Certainly not 3mms worth.

The spacers required are the same as normal, have a look at the Shimano tech docs. The q-factor of the M985 double is very narrow though, there’s only 4mm clearance between crank-arms and stays on my (skinny) Ti frame (73mm bb, one 2.5mm spacer). You’ll need to do your homework.

it’s a 73mm BB.

thx guys, I don’t want to make an expensive mistake … will dig into the tech

There’s nothing you can do then really. You may get away with a very thin spacer on the drive side, but bear in mind anything you do will mean the end cap/NDS crank have less purchase on the axle. I’d not be doing it.

As said above, if you think the chainline’s too narrow, you may well have other issues with crank clearance, particularly if you start messing around with spacing.

thx njee, no worries there are other cranks (and other frames)

Just grind 3mm off the non-drive side of the BB shell. It’s only a cheap frame 😆

Just of curiosity, what frame is it that won’t work with a standard XTR chainset?