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  1. #1
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    Can I use 9 speed chainrings on a 10 speed?

    I'm wanting to convert my 08 Stumpy to 2x10. Do I have to use 10 speed chainrings or can I use 9 speed rings. Specifically Race Face Race rings. I like the price and size availability of the Race Face rings.

    I want to run 24/36/bash ring and I can't find a 10 spd SLX 36 tooth.

    I'm changing to XT M780 shifters, XT M780 rear derailleur, SLX cassette and HG94 chain.

  2. #2
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    I am running a 9 sp. crank/chain rings with 10 sp. chain and cassette on my cross bike and it works fine. I think the 10 sp. rings are a tiny fraction thinner than the 9 sp. rings.

  3. #3
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    OK thanks. I read through most of the 13 page Dyna Sys 10 speed compatibility thread. Sounds like 9 speed rings will work fine.

    However now I am confused as to whether or not my 9 speed FD will work with the new 10 speed FD shifter. Has anybody tried using an XT 10 speed front shifter with a LX mega 9 front derailleur?

  4. #4
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    There have been no changes in FDR by default, Shimano and SRAM use the same config for front. It will work fine, with a 3 ring crank leave the XT shifter in 3 ring mode. If you remove the big ring and put a bash on, you still leave it in 3X mode. If you buy a 2X crank or a 2X specific derailleur like the SLX M665 (I think) then you use the 2x mode. From what I gathered, the 2X cranks have a different spacing that is similar to the middle-ring and big ring and when in that mode, it locks shifter on rings 2 and 3 only, it will not go to the granny ring. This can be read on techdocs.shimano.com, select Deore XT, then SL-M780 shifter. One of the docs on the right explains how to set it up in 2x mode. It does not explain the spacing though, many of us just assumed since it states to shift to the middle ring before turning that switch or it could break.

  5. #5
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    Good to know. I'm just waiting on my tax return to order the new parts. Hopefully it will all work well with the 9 speed cranks and front derailleur already on my bike.

  6. #6
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    Front shifting is the least sensitive to chain width changes. I've kept old rings on bikes with narrower chains every time we've added more gears in back. Every time it's worked just fine. Even if used with the old FD.

  7. #7
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    Can I use 9 speed chainrings on a 10 speed?

    I have the raceface 24/36/bash setup on a tallboy lt. The rings are stamped for use with 9 or 10 speed.

  8. #8
    The Original Suspect
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    Quote Originally Posted by pleepleus View Post
    OK thanks. I read through most of the 13 page Dyna Sys 10 speed compatibility thread. Sounds like 9 speed rings will work fine.

    However now I am confused as to whether or not my 9 speed FD will work with the new 10 speed FD shifter. Has anybody tried using an XT 10 speed front shifter with a LX mega 9 front derailleur?
    I just converted 9 to 10 and I am still using my SLX 9 sp front derailleur with XT front shifters and it works great. I am also running 9 sp RaceFace cranks and rings with zero problems with 10 sp chain or cassette. I have the same set up as you are upgrading to.

    Good luck

  9. #9
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    Quote Originally Posted by 4Crawler View Post
    I am running a 9 sp. crank/chain rings with 10 sp. chain and cassette on my cross bike and it works fine. I think the 10 sp. rings are a tiny fraction thinner than the 9 sp. rings.
    Just for grins yesterday, I stuck a new wheel w/ a 10sp cassette on my old Schwinn touring bike that has a 5sp triple crank. Stuck a 10sp KMC chain on there, dialed in the RD and it works like a charm. The front shifting is a bit sluggish but likely due to the chain rings not having any ramps or pins, but it was also sluggish with the old setup.

  10. #10
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    I went ahead and ordered the Race Face rings. haven't had the chance to try them out yet though. Took my bike to the shop for suspension service almost three weeks ago and haven't got it back yet. Don't ever buy a Specialized with a Brain shock. It takes them forever to service and it has to be sent to Specialized to be serviced.

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