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  1. #1
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    5-Spot chain stay and FD (mis)adventures

    Just wanted to put some pictures up in case anyone else has some suspicious looking marks on their chainstay.

    I was cleaning my bike today and found a mark on the chain stay, near the main pivot. At first, I thought it looked like there had been chainsuck and the chain got squashed against the chain stay. But when I put the FD into the small ring, the marks lined up. Prior to cleaning my bike, I had done some drops and descents over rough stuff in the small ring. I guess I must have used up enough travel to have the FD contact the chain stay. The o-ring on the shock showed that I did not achieve full travel during the ride.

    These chainstays originally came from a Flux, and it did have a small mark on it then. Definitely got worse after this weekend, and definitely not an incident exclusive to the 5-Spot.

    My FD is set up according to Shimano's recommendations, using their transparent-sitcker-with-recommended-gap method. The FD cage itself is parallel to the rings. I run a 2 ring setup (32/22). I have a DHX-A on the bike right now and sag is set up as per Fox's recommendation.

    At this point, I'm starting to wonder if the FD will have enough compliance (i.e. flex) such that it will deflect and take all the energy of the impact... or if it will be "super stiff for precise shifting" and transfer all the stress onto the seat tube and.....

    Oh well.. I guess I'll just have to remember not bomb down stuff in my small ring (rookie mistake)....
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  2. #2
    No, that's not phonetic
    Reputation: tscheezy's Avatar
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    Thanks for the heads up. There have been a few threads here on the topic. Here's one.

    Take home message: try to take the big hits when in the middle ring, or shave that low-hanging part off the der.
    My video techniques can be found in this thread.

  3. #3
    Elitest thrill junkie
    Reputation: Jayem's Avatar
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    Quote Originally Posted by techFiend
    My FD is set up according to Shimano's recommendations, using their transparent-sitcker-with-recommended-gap method. The FD cage itself is parallel to the rings. I run a 2 ring setup (32/22).

    That's probably the problem. The FD will probably clear when you're running 3 rings.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

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  4. #4
    FleshwoundGravityResearch
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    Quote Originally Posted by Jayem
    That's probably the problem. The FD will probably clear when you're running 3 rings.

    Nope. I am running 3 and I just checked to find that I have 'the mark'.

    Bummer.

  5. #5
    Full Monty Bike Bore
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    I think I've also clocked a similar mark on my 3 rings setup - which might help to explain why my front mech cage was all twisted a while back...
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  6. #6
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    Quote Originally Posted by tscheezy
    Take home message: try to take the big hits when in the middle ring, or shave that low-hanging part off the der.
    After one of the previous posts on this topic I did just as tscheezy said and modified my derailleur. had not made contact yet, but it could have. Plus playing with dremels is fun!

  7. #7
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    i noticed just a couple of days ago that I have two small marks there too. One from being in the middle ring and the other when in the small. I raised my FD up about a little to see if that helps. Shifting is still just as good as when it was set to Shimano's spec. I was suspect of this after the initial bike build. I still need to dump the air out of the main chamber to see if it clears now.

  8. #8
    As in sucking wind
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    When set up correctly with 3 rings, the FD will hit the stay while in the small ring, and will have a couple of mm clearance in the middle ring when fully compressed. This is using
    tscheezy's recommendation:

    Rest the end of a ruler on the bb shell on the non-drive side and measure along the seat tube to the bottom of the Der clamp. On an XTR front der (I assume the XT will be very similar) you need the bottom of the clamp 4 1/8" above the top of the bb shell. Any lower and you are screwing yourself and your bike.

  9. #9
    FleshwoundGravityResearch
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    Quote Originally Posted by dpdsurf
    i noticed just a couple of days ago that I have two small marks there too. One from being in the middle ring and the other when in the small. I raised my FD up about a little to see if that helps. Shifting is still just as good as when it was set to Shimano's spec. I was suspect of this after the initial bike build. I still need to dump the air out of the main chamber to see if it clears now.

    I had raised my der clamp up about 1/4" higher than proper setup and shifting was shty.

  10. #10
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    Quote Originally Posted by mtn hack
    I had raised my der clamp up about 1/4" higher than proper setup and shifting was shty.
    I raised mine 1/8". I just let all of the air out the my shock to check it and the bottom of the derailleur clears the swingarm by 1/8". Maybe try lowering yours slightly.

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