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  1. #1
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    Converted 2x crankset to 1x. Chain line/bb spacing question

    Recently converted my HD (2011, 142mm) to Sram XO 1x11. Bought the whole group except the crankset. Instead of forking out the extra cash, I just slapped a Wolf Tooth 32t narrow/wide on my existing XT 2x crankset. It works fine, but my chain line seems to be a little off when I'm in the granny. I was worried about prematurely waring my absurdly expensive cassette, so i played with the spacers on my shimano bottom bracket.

    Now I've got 3mm of spacers between the non-drive-side BB cup and the frame. And, on the drive side, I've got 1.5mm of spacers. This is exactly the opposite of what Ibis recommends.

    My solution has improved the chain line significantly. It is nearly perfect in sixth gear.

    QUESTIONS:

    Has anyone else had this when converting a 2x crankset to 1x?

    Do you think that I'm going to cause some sort of biomechanics problem in my body by not having my pedals evenly spaced away from the center line of the frame?

    Thanks!

  2. #2
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    I did a similar thing with my 2x X0 crankset (can still get a 1x spline if need be) but used a RaceFace 30T narrow/wide ring which has a ~2mm spacing vs larger flat ring for the bold thread and clearing the chain against the 104BCD arm, and moved the 2.5mm spacer to the non crank side (5mm total). Granny chain line is still a little extreme to me...

    don't know about the biomechanics potential issues - didn't think of that, then again I'm not sure the cranks are centered to start with...

    -Alain

  3. #3
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    Re: Converted 2x crankset to 1x. Chain line/bb spacing question

    Quote Originally Posted by circlesuponcircles View Post
    Recently converted my HD (2011, 142mm) to Sram XO 1x11. Bought the whole group except the crankset. Instead of forking out the extra cash, I just slapped a Wolf Tooth 32t narrow/wide on my existing XT 2x crankset. It works fine, but my chain line seems to be a little off when I'm in the granny. I was worried about prematurely waring my absurdly expensive cassette, so i played with the spacers on my shimano bottom bracket.

    Now I've got 3mm of spacers between the non-drive-side BB cup and the frame. And, on the drive side, I've got 1.5mm of spacers. This is exactly the opposite of what Ibis recommends.

    My solution has improved the chain line significantly. It is nearly perfect in sixth gear.

    QUESTIONS:

    Has anyone else had this when converting a 2x crankset to 1x?

    Do you think that I'm going to cause some sort of biomechanics problem in my body by not having my pedals evenly spaced away from the center line of the frame?

    Thanks!
    That is what I would have done. I find even the "proper" 1x cranks to be too far outboard for best performance.
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  4. #4
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    Cross Chaining Wear on Chainring

    Quote Originally Posted by circlesuponcircles View Post
    Recently converted my HD (2011, 142mm) to Sram XO 1x11. Bought the whole group except the crankset. Instead of forking out the extra cash, I just slapped a Wolf Tooth 32t narrow/wide on my existing XT 2x crankset. It works fine, but my chain line seems to be a little off when I'm in the granny. I was worried about prematurely waring my absurdly expensive cassette, so i played with the spacers on my shimano bottom bracket.

    Now I've got 3mm of spacers between the non-drive-side BB cup and the frame. And, on the drive side, I've got 1.5mm of spacers. This is exactly the opposite of what Ibis recommends.

    My solution has improved the chain line significantly. It is nearly perfect in sixth gear.

    QUESTIONS:

    Has anyone else had this when converting a 2x crankset to 1x?

    Do you think that I'm going to cause some sort of biomechanics problem in my body by not having my pedals evenly spaced away from the center line of the frame?

    Thanks!
    Did XX1 conversion the same way. Started with a 34T Wolftooth on the XTR crank, then a 30T after the 34T wore out causing a really noisy drivetrain at 400 miles. What happens is the aluminum teeth wear down much faster due to the cross-chaining loads, and is noticed by worsening chainsuck/noise.

    The 30T was more forgiving since chainline was better (spending less time in 42T, 36T), so got a whopping 500 miles out of that Wolftooth. Cassette is still fine, observed very little chainstretch, and would get 1000's of miles out of 2X XTR rings so cassette, chain, and maintenance is not the issue.

    I broke-down and switched yesterday to SRAM carbon XX1 crankset. Cross-chaining should be less/better. One issue is that the Wolftooth installs to the where the larger (outboard)chainring mounts on the 2X.

  5. #5
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    Quote Originally Posted by rathbone View Post
    I broke-down and switched yesterday to SRAM carbon XX1 crankset. Cross-chaining should be less/better. One issue is that the Wolftooth installs to the where the larger (outboard)chainring mounts on the 2X.
    I don't think there is anything unique about SRAM XX1 crankset - any 1x crank will do... so you could have saved a bunch of $$ getting a 1x (or 2x and replace the spider) X0/X9 10 speed cranks, or others. Unlike Shimano the spider is replaceable (I have 2 different 2x spider - originally 120/80 BCD then replaced with standard 104/64 BCD + bash guard, but can get 1x spider or 1x ring that mounts directly as well and keep the carbon cranks).

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