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  1. #1
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    Flux - setting up v-brakes w/ bosses

    I'm building my Flux this weekend. As many are aware, I'm on a tight budget and am forced to use my old White Industries non-disc wheelset with my old XT v-brakes.

    I mounted the v-brake bosses at 10" from axle centerline, as per Greg at Turner. With the v-brake spring stud in the center hole of the bosses, the brakes don't open enough to get a puny Specialized Fast Trak Pro 2.0 tire in there. If I put the spring stud in the upper hole of the bosses, the plate that the brake pad stud mounts to is not parallel with the rim. Those familiar with the Shimano parallel push brakes should know what I'm talking about. Is that a problem? I'm guessing I'll still be able to adjust the pads so they hit the rims correctly. One more problem with setting it up that way, is that the brakes open so much that the brake pad holders will hit the upper stays on the rear triangle. The middle hole feels like the correct hole (perfect brake tension, perfect alignment), but the brakes don't open enough to clear the rear tire. My old frame did not have this problem.

    Does anybody have any suggestions? I'll get discs in due time, so please don't suggest that as a solution. Thanks.

    Roy

    edit - old frame bosses are 3.25" apart. new frame bosses are 3" apart.
    Last edited by royta; 03-04-2006 at 07:34 AM.

  2. #2
    Natl. Champ DH Poser/Hack
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    got yer pm pal. heres my thoughts. hard to say not seein it but id say ya have 2 options. my fave is to mount in the center hole and add some spring tension by simply bendin the linear springs out some with yer fingers. be sure the pre load screws are not more than 1/2 way in so ya retain adjustability. the other option is to do as ya mentioned and mount in the 3rd hole then re adjust the pads from there but this can add too much tension at low pre load sometimes. experament a bit and see what shakes out. the goal is to have the brake arms pad mounting surface on the same plain as the rims brakeing surface when the pad meets the rim. good luck pal.
    No, I'm NOT back!

  3. #3
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    In the middle hole, it's not the spring tension that's the problem. The arms physically won't open far enough to clear the tire. In order to install the tire, I would have to remove one of the brake arms from the boss. That kind of defeats the purpose of a QR.

    That's the way I always thought it was supposed to be, the brake stud plate on the same plane as the braking surface. Or at least as close as possible. In the upper hole, it's not even close, and the spring tension is HIGH. I've got forearm pump just thinking about it. I'm thinking I might be forced to take one set of non parallel push arms from my wife's bike to use on the rear of my bike. I believe they open wider, due to not having the linkage in there.

  4. #4
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    OK, I got it figured out. Look at this diagram. See the parts noted by number 4? I swapped the thick and thin concave adjustable collars. They originally come with the thick ones to the inside. By putting them to the outside, I have given myself more tire clearance.

    Thanks for nothing cactuscorn.

    Roy

  5. #5
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    I also want to make it clear, that the only problem was opening the brakes far enough in order to remove and install the rear tire.

  6. #6
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    I spoke too soon. After moving the collars and adjusting the brakes to the rim, I am still unable to remove the rear tire. I'm going to experiment with the boss location. If I move them closer to the axle, this will force me to move the brakes higher up in their adjustment slot. Hopefully this will allow the arms to open farther before the back side of the pad comes into contact with the brake arm parallel linkage thingy.

  7. #7
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    Quote Originally Posted by royta
    I spoke too soon. After moving the collars and adjusting the brakes to the rim, I am still unable to remove the rear tire. I'm going to experiment with the boss location. If I move them closer to the axle, this will force me to move the brakes higher up in their adjustment slot. Hopefully this will allow the arms to open farther before the back side of the pad comes into contact with the brake arm parallel linkage thingy.
    Moving the bosses down, and the pads up in the adjustment slot, allowed the arms to open farther out before the backside of the pad hit the parallel linkage thingy. I'm off to the races!

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