Dura-Ace FD on an RFX possible ?- Mtbr.com
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  1. #1
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    Dura-Ace FD on an RFX possible ?

    I'll be running an XTR crankset with a 22/32 or 22/36 and an e.13 drs. Just wondering if a Dura-ace is possible since it'll be only 2 front rings? Anyone with experience or know if this will/won't work?

  2. #2
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    Why not an off-road group derailleur?

  3. #3
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    Quote Originally Posted by Jerk_Chicken
    Why not an off-road group derailleur?
    Well, I ask because I'm coming from a weight weenie background so if I can shave some grams on a derailleur that would be nice. Don't get me wrong, the whole build however will be solid.

    The DA's are about 85 grams!

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    I would just get a Nitrous and put a 66 on there.

  5. #5
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    85g? That's got to be a braze on. Once you add the clamp, back into normal front derailer range, likely.

    Do check out the new SLX two ring specific front derailer. Compact tail, less likely to get smacked by your chainstay at full travel. Drill and file out an SLX two ring derailer if you feel the need to lose grams when building an RFX. Drill and file your DRS, oh, MRP has a new ultra light two ring chain guide available now.

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    Quote Originally Posted by Jerk_Chicken
    I would just get a Nitrous and put a 66 on there.
    Funny, however I already have a nitrous, a 66 would look like a real chopper.

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    Quote Originally Posted by sparrow
    85g? That's got to be a braze on. Once you add the clamp, back into normal front derailer range, likely.

    Do check out the new SLX two ring specific front derailer. Compact tail, less likely to get smacked by your chainstay at full travel. Drill and file out an SLX two ring derailer if you feel the need to lose grams when building an RFX. Drill and file your DRS, oh, MRP has a new ultra light two ring chain guide available now.
    yeah, you're right for braze style. The regular is 105 g. Not even sure it would be able to do the proper swing/pull, etc. They do have 34.9 however.

  8. #8
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    Quote Originally Posted by protocol_droid
    Well, I ask because I'm coming from a weight weenie background so if I can shave some grams on a derailleur that would be nice. Don't get me wrong, the whole build however will be solid.

    The DA's are about 85 grams!
    Just run without grips. Instant weight savings!

    I would seriously look at the SLX , though you could always do XTR. A more compact cage would be a godsend, as the RFX does not seem to like longer cages, due to suspension travel and pivot positioning. I had lots of chain rub on the bottom cage crossmember when in the granny gear till I took a dremel to my X9.

  9. #9
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    nope. thats a no go. the road and mtn f der's and shifter use a diff cable pull ratio and are not at all compatable. also the cage profile is way too large for those gears. and like sparrow says, itll hit the stays on compression. on top of all that, its just kinda silly. sorry.
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  10. #10
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    Quote Originally Posted by cactuscorn
    nope. thats a no go. the road and mtn f der's and shifter use a diff cable pull ratio and are not at all compatable. also the cage profile is way too large for those gears. and like sparrow says, itll hit the stays on compression. on top of all that, its just kinda silly. sorry.
    I had to give it the old college try.

  11. #11
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    it woulda been original, thats for sure. you could always run a old 9 spd dur-ah-chee cassette and r der like the dh boys. or... be the 1st guy on the mtn with bar cons!

    see ya in a few weeks pal.
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  12. #12
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    Quote Originally Posted by cactuscorn
    nope. thats a no go. the road and mtn f der's and shifter use a diff cable pull ratio and are not at all compatable. also the cage profile is way too large for those gears. and like sparrow says, itll hit the stays on compression. on top of all that, its just kinda silly. sorry.
    The ratios are the same. The problem is road FD are bottom pull and an RFX requires top pull.
    I ran a 9sp Dura-Ace on my old 575 for a couple of years and it worked fine. Mtb FD's are rediculously overbuilt for what they have to do.

  13. #13
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    Quote Originally Posted by cactuscorn
    it woulda been original, thats for sure. you could always run a old 9 spd dur-ah-chee cassette and r der like the dh boys. or... be the 1st guy on the mtn with bar cons!

    see ya in a few weeks pal.
    I'd still like to be able to pedal uphill. I'm looking at the old 950 series xtr now since they were the lightest of the mountain series.

    see ya

  14. #14
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    with xo shifters and a xtr r der ill guess? trust me, the pull ratios are not the same. wish i could find the #'s for ya. there may also be a issue with throw and chainline compatability. a dura ace is set up for a 43,5 and a xtr for 50mm meanin its gonna be hard pressed to hit the big ring and the middle ring may be sketchy too.

    is the mtn stuff overbuilt? maybe some of it, but i prefer a accurate shift in rough conditions and ill take a system that works perfectly instead of "fine". i still see no reason to use a non compatable part just to save 30g. if yer THAT worried, drill a hole in somethin or dig up those old throw away cnc'ed parts that never worked outta the box or wouldnt last a month. remember how light those were?

    this isnt a attack, just a rant. i feel the same way about overbuilt bikes too. folks try too hard in both directions rather than build a bike that works for their needs and doesnt need a crane to get it in the stand for constant service.
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  15. #15
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    Sorry, I should have specified I used a 2 ring set up on the front. Obviously a standard dura ace FD (non-triple) won't have the throw for a 3 ring front set up. But has nothing to do with pull ratios, which remain the same across the board. This is a fairly common set up for the weight weenies/xc race crowd.

    FWIW, I find no discernable diff between the DA shifing and the XTR I now have on my RFX.
    (X9 trigger shifers BTW).

  16. #16
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    Actually, with XTR rear. Also, just trying to save weight where things aren't critical like the derailleurs, cabling, grips, seat, etc. I certainly wouldn't be putting a syntace f99 and a schmolke bar onto this bike. So the older XTR front derailleurs are <110 grams whereas the newer ones are over 150gms. I think I'll be going this route seeing it looks next to impossible to use a DA.

    BTW, I bought SSinga's 08 talas 36 and it looks like mount everest next to my ant hill sid worldcup!! can't wait to get this thing up and running!

  17. #17
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    Quote Originally Posted by cactuscorn
    trust me, the pull ratios are not the same. wish i could find the #'s for ya. .


    PUT UP OR SHUT UP YOU OLD COOT!!!!

  18. #18
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    ill have to call shimano for the specifics. i discovered this when tryin to mount a flat bar and mtn shifters on a road bike for a custy. couldnt make the damn thing work up front so a call to john barnett was made and the answer given. a large capacity mtn f der was ordered then installed and the problem solved.
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  19. #19
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    road front derailers are narrower than ATB. That's why road shifters have that "soft" trim click on the front shifter (STI or flat bar road...)

  20. #20
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    check this thread out with nino's post.

    http://forums.mtbr.com/showthread.php?t=441523

    looks like a little adapter can make the bottom pull work. I won't be doing this, but interesting nonetheless.

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