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Discussion Starter · #1 ·
I've got a Kona Unit that came stock with some Race Face cranks and a 68x113 BB. I came up with some newer XT cranks (not the integrated ones) and had them installed by my LBS. Turns out a 68x113 ES 71 BB did not give a good chainline so we were left with using an ES30 73x121 with some spacer I think.Well it turns out the LBS cross-threaded the dang thing (BB cup) on there but hopefully it will be fine because the cup is plastic. That's a whole nother story.

But anyway my question is what size/model BB should give me the proper chainline with my new cranks? Obviously they used the ES30 but I don't know. I didn't like the idea of a plastic cup. Will an ES30 hold up?
 

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Eltbee said:
I've got a Kona Unit that came stock with some Race Face cranks and a 68x113 BB. I came up with some newer XT cranks (not the integrated ones) and had them installed by my LBS. Turns out a 68x113 ES 71 BB did not give a good chainline so we were left with using an ES30 73x121 with some spacer I think.Well it turns out the LBS cross-threaded the dang thing (BB cup) on there but hopefully it will be fine because the cup is plastic. That's a whole nother story.

But anyway my question is what size/model BB should give me the proper chainline with my new cranks? Obviously they used the ES30 but I don't know. I didn't like the idea of a plastic cup. Will an ES30 hold up?
Are they XT Octalink cranks? If so, the 68x113 ES71 should have been fine (I run that on my older Kona, and I don't think that spec's changed on their bikes). If it's a square taper XT, then it probably took a 68x110.

Good luck,

-Que?
 

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Eltbee said:
Yes. We tried a ES71 113x68 and it gave the chainline problem. I was really hoping to be able to use that too.
OK...I got it now. So by chainline problem, you mean that the chain doesn't follow a straingt line from the chainring to the rear cog. Correct? Or is the crank hitting the chainstay?

If it's the former, then the solution might be to use a regular cassette hub with spacers so that you can get that rear cog straight in line with the chainring (that's what I do). Or are you using a SS hub?

-Que?
 

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Discussion Starter · #6 ·
Yeah. I mean I suppose it would have worked but the LBS guy was paying, thankfully, attention to detail. He got the Park chinline tool out and it was a bit short.

Correct. I have a SS rear hub with a freewheel. This would be a good excuse to upgrade to a ca$$ette hub but for the time being I'll let it ride. :)

Also I just got back from the LBS and the cup on my ES30 is a bit out of spec so it was not cross-threaded after all.
 

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That crank was desingned for 3 rings, you're using the big ring space for a bash guard and using the middle for your ring, right? If so the long spindle of the 68x118 should work fine but will be easier to have a conventional sized BB and fix the chainline with spacers on the rear but you stated that you are using a SS hub probably that was the only way to go.
 
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