Finishing up a build with:

Old Stylo crank mated to Absolute Black oval chainring.
GXP BB mated to the 68mm BB shell.
XT 11 spd cassette (no XD drive available for the rear wheel, so this is a good option for me)

When in the 42 T sprocket at the back the chain line is not too great. When I put the chain in the middle rear sprocket you can see the chainring on the stylo is too far outboard relative too the cassette.

Anyway, heres my thinking.

The gxp has two 3mm spacers for use on a 73mm bb shell,right? As the drive side crank on gxp setups “floats” I seem to remember that if I install a 3mm spacer on the NON drive side it effectively pulls the crank 3mm inboard??

Is my thinking correct there, hope i make sense? lol

As always, thanks for info guys! 🙂

I’m still confused about this but on my GXP (1*11) there was only one spacer on the drive side. This was on a hope BB.

I’ve recently removed the hope (to clean it) just to try a SRAM GXP BB and I fitted it with no spacers as per the instructions.

I realise this adds nothing but I’m confused why the hope was fitted with one spacer.

Both BB run fine and no issue with chainline.

Your Hope BB isn’t GXP specific, if you run it without the spacer then there’s a chance you’ll crush the sleeve between the two cups. Re adding a spacer to the non-drive side, yes, it will move the chainline across (and everything else, though doubtful you’d notice you’re pedalling a few mm on the wonk).