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  1. #1
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    104mm or 94mm ???

    I'm sure that this has been discussed but the search function is not working for me at the moment sooooo... I have shimano xl hollowtech cranks and need a new middle ring and I was looking at RF but I am not sure if I need 104mm or 94mm and what is this measurement referring to?

  2. #2
    Do It Yourself
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    Shimano hasn't made a 94mm BCD crankset in over 10 years. You'll need a 104mm BCD. I found the Salsa rings to be more durable and cost less than the RF.
    Long Live Long Rides

  3. #3
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    Quote Originally Posted by Homebrew
    Shimano hasn't made a 94mm BCD crankset in over 10 years. You'll need a 104mm BCD. I found the Salsa rings to be more durable and cost less than the RF.
    Cheers Homebrew.

  4. #4
    mechmann_mtb
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    BCD refers to the Diameter of the Circle that goes through the center of all of the Bolts of the chain ring.

    Bolt Circle Diamter is what BCD is an acronym for.

  5. #5
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    Quote Originally Posted by mechmann_mtb
    BCD refers to the Diameter of the Circle that goes through the center of all of the Bolts of the chain ring.

    Bolt Circle Diamter is what BCD is an acronym for.

    Seems like someone mentioned in another thread that if you are running shimano XT cranks and go with another brand chainring you will need to get different chainring bolts. Something about the shimano bolts only being 1/2 threaded or something. Is that right?

  6. #6
    mechmann_mtb
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    i think that depends on what CR you are using and what arrangement you have.

    if you are putting a bashring on then that can complicate things. but most bashrings are much thicker than the big CR.

    i don't have any experience with raceface (or any other rings as far as shifting).

    the Etralite CR that i have required me to grind down the length of the CR bolts. the CR nuts that are built into the CR are blind (the hole doesn't go all the way through). i accomplished this by putting them on an allen wrench and then grinding them down on my angle grinder.

  7. #7
    Do It Yourself
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    Quote Originally Posted by noosa2
    Seems like someone mentioned in another thread that if you are running shimano XT cranks and go with another brand chainring you will need to get different chainring bolts. Something about the shimano bolts only being 1/2 threaded or something. Is that right?

    For the new M760 XT cranks, that's correct. Even an older XT chainring won't fit with the stock bolts. The stock chainring bolts are only half threaded and bottom out before securing the ring. I've tried RF, Salsa, and older XT and none would fit properly with the stock bolts. I replaced the chainring nuts with shorter ones from old XTR chainrings and worked fine. The other solution would be full threaded bolts.
    Long Live Long Rides

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