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Discussion Starter · #1 ·
Howdy

In order to get a chailine that works well with my new SLX crankset I've had to swap the two spacers on the drive side and one on the left side from the stock crankset set-up - to two on the left and one on the drive side. This means my pedal/crank arm is now more left of center than the drive side.
Does this matter?

Thanks
 

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Old man on a bike
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Only really to you, more aesthetics than anything. Assume you have a 68mm shell on that frame?
 

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I have a bike whose chainline would benefit from redistributing the spacers as you describe. The only problem is that when I do so, the drive side crank ends up being closer to the chainstay. There is no interference between those parts, but moving it over that little bit increases the likelihood that my heal will rub the chainstay while pedaling. Therefore, I've stayed with the recommended spacer placement.

But, if you find that the alternate, asymmetrical spacer placement works for you, then there's no reason not to use it.
 

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Discussion Starter · #4 ·
It is a 68mm shell. The bike came stock with a cheaper Shimano BB and the spacers were as described above. The spacers remained the same for a RaceFace crankset as well.

Is it normal for the chainline to change that much between cranksets?

My drive side crankarm is now closer to the chainstay than the left side crankarm. Should the asymetry of this set-up have an effect on pedaling?

Thanks again.
 

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macdeal said:
It is a 68mm shell. The bike came stock with a cheaper Shimano BB and the spacers were as described above. The spacers remained the same for a RaceFace crankset as well.

Is it normal for the chainline to change that much between cranksets?
One of the problems, as I see it anyway, with the Hollowtech II cranksets is that Shimano went with a one size fits all approach. Rather than making cranks with different spindle lengths, they instead use a single crank spindle length. You have to use spacers in order to adapt that one length to different BB shell widths.

So, for a 68mm shell width, the change in chainline when moving from square taper, ISIS, or Hollowtech I to Hollowtech II is not unexpected.
My drive side crankarm is now closer to the chainstay than the left side crankarm. Should the asymetry of this set-up have an effect on pedaling?
There's no way for me to know. You'll have to try it yourself to see if affects your riding. I have no doubt that some riders would be able to immediately detect a difference, while others would be blissfully unaware of the asymmetry.
 
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