Chain line help - Hollowtech 2

[Roasted]

Triple chainset alignment suffered with the popularity of wide tyres, (2.4s+, early 2000s but still with 135 rear spacing) meaning its common for those running triples on fixed-length bb axles like ht2 to find the chainset's 5mm or so out in the breeze. Misuse of spacers is common - adoption of double and bash an ugly alternative.

That's good info and may resort to abuse of the spacers. I want to stick 3x9 on this bike, I have lots of 1x9 and don't really want 2x9, but may entertain it if I can't find a better solution.

Shimanos current double crankset that is supposed to be suitable for 135mm dropout spacing has a 48.8mm chainline and their 1x cranksets are 52mm!! They've been pushing chainline out for a while now.

I'm guessing this Deore crankset is around the same preiod as the XT one you have and it is listed as having a 50mm chainline:

FC-M590 triple

So it looks like what you have is 'correct' according to Shimano.

If I want a new crankset for a 135 bike now I tend to default to the Stronglight TD2 ones that Spa Cycles sell for this exact reason. I'm not even close to an expert on these things but just prefer it if my chainline is where I think it should be.

Those deore are pretty much the same as my XT. This XT chainset has been on a Cannondale Killer-V and Trek 8700 before and I don't remember the chainline being this bad, but maybe I didn't care as much back then.

This is a low cost build so gotta make do with what I have, although I do have RaceFace Turbine cranks that would work on this project. They just needs some new rings and they'll be good to go.

 

[Roasted]

I think it's sorted.

I checked the BB width and it's definitely 68mm. I moved 1 spacer onto the NDS and the chainline looks better. Small to large clears the tyre fine, middle looks straight going to 5 and large to small lines up quite nicely. I think I'll leave it like that. Thanks for all the help.

 

[legrandefromage]

I run lots of triple chainsets with external bbs, on older frames - I just move the spacers about until things work