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  1. #1
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    Need help guys- chainring spacers

    I'm running xt crank, with absolute black chainring, and new xt8000 1x11 cassette. I would like to try and add a chainring shim to help with chainline. Does anyone have a good online source and I am assuming I will need longer bolts, correct?

  2. #2
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    Amazon.com : Wheels Manufacturing 0.6mm Chainring Spacer (Bag of 20) : Bike Chainrings And Accessories : Sports & Outdoors
    Depends on how thick your shim is going to be. As long as the nut still protrudes into the crank spider you should be good. If not, you need the next longer bolt/nut setup.
    Can you move your BB shims around?

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    Not sure about the bb, it's a Chris King

  4. #4
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    I got 3mm spacers and 12mm bolts from Titanium Bolts, Titanium Fastener, Bike Parts Toronto, Bike Bolts . One Up sells 2mm spacers , as do many others on Ebay. You'll need minimum 10mm long bolts.

  5. #5
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    I'm running an absolute black 32t oval with 2mm spacers built in, and it is not enough. Can I use extra 2mm spacers with this ring using longer bolts?

  6. #6
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    I'd say you shouldn't. There are no nuts to locate the chainring.
    If you have BB spacers on the drive side BB you could move them to the non-drive side.

  7. #7
    jae
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    Quote Originally Posted by Slash5 View Post
    Depends on how thick your shim is going to be. As long as the nut still protrudes into the crank spider you should be good.
    How much protrusion into the crank tabs is necessary? In my case, going 1x on a Shimano XT crankset using a Race Face 32t NW ring and shorter 6mm steel chainring bolts. The female nut goes about 1.5mm into the tabs. My worry is if the tabs might be damaged with partial insertion depth. OTOH, this doesn't seem to be an issue with an outer AL chainring (when running middle and outer rings with longer bolts) where the insertion is also only partial. Am I worried over nothing?

  8. #8
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    Here is a pic of my front ring with the AB ring with built in 2mm spacers. I've got plenty of clearance to shift the ring over, I just need to figure a way to shim it.
    Attached Images Attached Images  

  9. #9
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    If you can live with 30t you could buy one for the 64bcd position and get the chainline you're looking for.

  10. #10
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    It would depend on how tight the tolerances of the shim is. If the hole in the shim is a good fit on the nut then this might work:
    Find a chainring nut that from the outside will go through the spider and into the shim but not interfere with the chainring to shim interface. Drill the threads out on the nut so that the bolt goes through. You would likely have to add a chamfer to the flanged end of the nut so the bolt will fully seat.
    Put the nut in from the outside and put the bolt through it and thread into the chainring. The nut will act like a locating sleeve.

  11. #11
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    Also, it appears you have one shim on your BB that could be moved to the non-drive side.

  12. #12
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    Quote Originally Posted by Slash5 View Post
    It would depend on how tight the tolerances of the shim is. If the hole in the shim is a good fit on the nut then this might work:
    Find a chainring nut that from the outside will go through the spider and into the shim but not interfere with the chainring to shim interface. Drill the threads out on the nut so that the bolt goes through. You would likely have to add a chamfer to the flanged end of the nut so the bolt will fully seat.
    Put the nut in from the outside and put the bolt through it and thread into the chainring. The nut will act like a locating sleeve.
    you lost me.

  13. #13
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    You use the drilled out nut as a bushing to connect the spider, shim and chainring. The shim couples the chainring and nut together, locating everything in position. To do this, the nut has to be inserted from the outside of the spider, backwards to the usual.
    I just tried a shim I had in my parts box with a nut and 30T N/W chainring and it looks pretty good.
    The trick is going to be having the length of the nut just long enough to enter the shim but not bottom out on the chainring. If it does you won't get any clamping force between the spider and chainring.

    I've shortened nuts on a belt sander several times. Hard to find single ring bolts and nuts sometimes locally.

  14. #14
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    It looks like you can change the BB spacersName:  IMG_0213a.JPG
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Size:  93.1 KB

    These look similar to the shimano ones I have. You may be able to get two at half thickness. Put one in this side and on in the otherside (with the one that's already there.

    Mine, I used a combination of bb spacers, crank washers and cassette spacer to get the chain line right.

  15. #15
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    well, I moved the bb spacer to the non-drive side, didn't help. I then installed a sram chain, and that helped a lot, I can get 3 full back pedals before it jumps off the 42t, and I am very happy with that!

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    Thanks for the update jd, what SRAM chain did you use? I was considering using an X-1 chain but chose the XT chain as I assumed it would work better.

    I also tried shifting my AB oval 32t 2.5mm inwards by moving the BB spacer to the non drive side with no improvement. Theoretically my drivetrain is at 44.5mm

    It's possible the 42t backpedalling problem goes away after the XT chain loosens up. Unfortunately, my previous bike (new M8000 drivetrain, 48mm chainline) got stolen before I could find out

    As for the spacers, they should work with the AB rings. IMO the tabs on the rings are more for ease of installation than structural reinforcement. I've already ordered the spacers so I'll try them out anyways. But if a chain swap works, I'll probably just do that instead.

  17. #17
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    I believe it was the sram pc-1170

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