[hardrocx]

Hi

I have just purchased the e-thirteen XCX and am trying to make it fit on a Sram XX GXP 166Q-factor 39-teeth crank. I have a 68mm hubshell and a BlackBox GXP bottom bracket. The problem that's occuring is that I can't get the chainguard far enough to the right. I have tried 2x0,5mm spacers AND 2x2,5mm spacers on the drive side and then the XCX, the bracket and the crank itself. I think I've tried all possible spacer-options, but can't seem to figure out how this could possibly work. Please help

Martin

 

[PhilipW]

Hi Martin!
The XX crankset (and most of the other 2011 dual ring cranksets) are not directly compatible with our BB mount XCX, due to the design of the crankset. The current XCX is designed around a 47.5-50mm chainline...which is typically the middle ring position of most external bearing triple/single cranksets.

In short, chainline is measured from the center of the BB shell to the chainring teeth (usually the middle ring position) for triple and single ring setups. For a dual ring setup, this measurement is between the two sets of rings. The XX crankset chainline is 49.5mm between the rings, so your chainring position for your 39T ring is likely between 53mm and 54mm.

In short, the only way to make the current BB mount XCX work with your crankset (currently) is to space the chainring inboard 3-4mm with chainring spacers, or M8 washers.

Cheers!
philip @ e*thirteen/the Hive

 

[hardrocx]

I ended up with a slightly different solution. You were off course right about the chainline on the outer chainring. I think it's 52,5mm or so.

Setup (68mm shell)
Left side:
Bottom bracket
2,5mm spacer

Right side:
Bottom bracket
Backplate XCX
2x0,5mm spacers
2,5mm spacer

With this setup I was lacking approx 3mm of clearance on the right side of the chainguard. I solved this by putting a 3mm washer between the plastic part on the chainguard and the metal backplate. The washer had a inner diameter of 8mm so it fit perfectly around the bolt attachment. With some loctite on the screw and some carbon-mounting-spray, I'm convinced that this is going to be a well-working solution. I'm looking forward to testing it out tomorrow.

Martin