XT8000 cranks and Eagle ... chainline or other issues?

The plan was to run my Salsa Cutthroat with Shimano GRX 1x and XT8000 cranks. I already have the cranks, Wolftooth chainring, and crank power meter. The bike has boost spacing …15x110 & 12x148.

The cranks themselves have a 50.4mm chainline when used with Shimano chainrings. Wolftooth says their XT8000 compatible chainrings correct for a 49mm, 11 speed chainline and are compatible with 11 speed and Eagle chains.

Looks like 12 speed cranksets have a 52mm chainline for the most part though, so my cranks and Wolftooth ring will be 3mm inboard right? Will that be an issue? Can I shim the crankset out 1 or 2mm to get close to 52mm?

I’m sure I’ll be spending alot of time in the big cogs, so I was wondering if the chainline being slightly inboard could be OK? I’d rather not buy a new crankset but if I had too XT8100 would work with my PM.

Any tips are appreciated. Thanks!!

49mm is the ideal boost chainline, but since you’re running 12 speed you’ll likely have the following issue:

“ 1. If you are running 12 speed, the clearances are so small between chain and cassette that you MUST run a boost spaced chainring with a boost spaced bike. If you don’t, the chain will “tick” on the next bigger cog when in the smallest 2-3 cogs on the cassette.”

From Wolf Tooth

2 Likes

I saw that and left more confused. It seems they’re talking about 11 speed cassettes when mentioning the 49mm spacing.

I’ll reach out to Wolftooth, but I figured some folks here may have run into similar issues.

Yeah that’s correct. I’m not familiar with GRX cranks: do you have any spacers on the non-drive side? If so you could move them to the drive side and run some pedal washers on the left crank to even out your feet. But then you might run into clearance issues with the crank and NDS chain stay, or your left heel.

Probably getting a boost crank is the ideal solution. I did a quick search and I don’t think you can get shimano compatible chainrings with no offset, which would be a nice solution for keeping your GRX cranks

1 Like

Do you already have the drivetrain? If not, you could always go with 11-speed

1 Like

I’m also confused and I’m glad mine all came with the bike.
All I wanted to say is have you seen this page and does it help any? M8000 is listed in the table.

1 Like

I’m running 1x with XT8000 cranks…the Cutthroat has a MTB sized bottom bracket. That only adds to the confusion! :rofl: I finally found all the parts for an AXS mullet so I definitely want to go that route.

@gvmcd I’ll check that out…thanks!!

Whoops, reading comprehension fail on my part.

1 Like

No worries haha! Appreciate the help!!

So it looks like Shimano makes MTB cranks with 3mm outboard spacing. Guess that’s what you’ll need if you can’t adjust yours with spacers. But I bet you can?

This one has a 53.4mm chainline, so your wolf tooth rings would correct it to 52 I think:

Or XT8100 as you mentioned, with stock chainring instead of wolf tooth.

I think you’ll be able to add a 2.5mm spacer to the drive side of your existing cranks and make it work though. Can’t hurt to try since you have it already.

1 Like

Can’t hurt to try! Thanks for the help.

1 Like

I’m way more familiar with road bikes so I had no idea the rabbit hole I was about to go down :exploding_head::nerd_face::exploding_head:

I got my crank from REI and the description said it was 1x and for 148 mm O.L.D. frames. There are holes for a second ring and no B1 or B2 markers indicating boost.


Did you get a power meter installed on the crank aftermarket?

Bought it ready to ride from 4iiii. I think it’s actually an M8100 crank arm.

1 Like

I think you’ll be fine.

Yes.

You can buy some BB spacers if it’s BSA, or 24mm spindle spacers if it’s PressFit, and shift the crankset outboard 1mm, maybe 2mm. You should still have enough thread engagement with 1mm, for sure.

1 Like