which to tune first? rd first then fd or is it the other way around?- Mtbr.com
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  1. #1
    外国人
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    which to tune first? rd first then fd or is it the other way around?

    bought a beater bike with the plan of stripping it down and building it up again so that i would learn how it is done. from what i've read, i think i should tune the rd first before the fd?

    many thanks!
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  2. #2
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    I like to mount both derailleurs before adjusting them, so I must at least make an initial stab at adjusting the front first. So I iterate:

    1) Adjust front
    2) Dial in the rear
    3) Revisit the front and dial out any rubbing caused by cross-chaining

    I can't really do step 3 until after step 2.

    And honestly, I don't obsess much about the order in which I do things. On the bike I'm building now, I will adjust the rear derailleur first, because I haven't yet ordered the front derailleur. When I do get the front derailleur and adjust it, I'll revisit the rear shifting as well, just to be sure everything is dialed.

  3. #3
    Cantankerous Old Fart
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    For 3X8 or 3X9:

    Make sure the FD is mounted square & in the proper relationship up/down to the largest chainring. EDIT: Adjust cable length so that the FD is roughly centerd on the center chainring W/the shifter in the appropriate gear.

    The rear adjustment is not dependant on the front (in theory) adjust the rear RD by cable length to be precicely inline (centered) W/one of the center cogs (5) W/the shifter in the appropriate indicated gear.

    Now, W/the chain on the center chainring, adjust the FD so that then chain is centered in the FD W/the shifter in the appropriate gear.

    Go back to the RD, shift to the largest cog, check that the RD is centered on that cog. If not adjust the RD (low) limit. Do the same W/the smallest cog. (high limit).

    Go back to the FD, W/the chain in the center chain ring, check for clearance on the sides of the FD in the largest & smallest cog. It should be equal.

    Set the low/high limits on the FD as you did for the RD.

    Road test & fine tune W/the limit & cable adjustments.

    In theory you should be able to shift to any rear cog in either the large or small chainring W/O any chain rubbing on the FD.

    I practice you may experience some small amount of rubbing on the FD when the chain is in the largest chainring while in the largest rear cog & vice versa.(small/small)

    You should be able to use any rear cog while in the center chainring W/O rubbing though.
    Last edited by XCSKIBUM; 04-29-2011 at 06:12 AM.
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  4. #4
    bi-winning
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    Quote Originally Posted by JonathanGennick
    I like to mount both derailleurs before adjusting them, so I must at least make an initial stab at adjusting the front first. So I iterate:

    1) Adjust front
    2) Dial in the rear
    3) Revisit the front and dial out any rubbing

    I can't really do step 3 until after step 2.

    And honestly, I don't obsess much about the order in which I do things.
    +1. Thanks for saving me the typing.
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  5. #5
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    Quote Originally Posted by XCSKIBUM
    I practice you may experience some small amount of rubbing on the FD when the chain is in the largest chainring while in the largest rear cog & vice versa.(small/small)
    +1. I no longer obsess about dialing out that last bit of rubbing. I dial it out if I can. Otherwise, I leave it to serve as a useful warning for when I'm riding in a less than optimal gear combination.

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