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  1. #1
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    2 Sets of Wheels, One Rubs, One doesn't, Need Very Small Washers/Shims

    Hey, I recently bought a new set of wheels for my 29er. I'm using Magura Marta brakes. With my old wheels, the roll was perfect, not a touch between rotor and pad. However, when I put the new wheels on, the rotor/hub combo was so different that I couldn't even get them to roll without any rub, much less to the point where I can run both sets of wheels with out any adjustment. With the help of the LBS, I got some spacers that are .9mm thick and put them between the rotor and the hub on my new wheels. This works great for the front, but they are too thick for the back and move the rotor too much. Does anybody know where I can find some washer/shim for my back wheel that would be somewhere in the .25-.5mm range? Has anybody else had a problem like this when trying to run 2 sets of wheels on the same brake setup? Thanks, Chuck
    If you ever see a turtle on a telephone pole, remember he had help getting there. Is there anything beer can't do?

  2. #2
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    pop/beer can?

  3. #3
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    The problem you describe is common when using different wheelsets with the same frame. I used to have 2 sets of wheels for my Las Cruces cross bike: one with knobbies for the trail and another with indoor trainer tires. I couldn't get the calipers adjusted to accommodate both wheelsets, granted the wheels are from different XT model years; I've since given up and just stopped riding my bike on trainers. There's just minute differences between wheel hubs such that it's difficult to use two wheelsets on a bike, especially with the tight tolerances of disc brakes.

    To answer your question, you can get very thin shims from hobby stores that sell radio controlled vehicles. Back when I was into RC stuff, the bearings would often need some shims as the gears worn down.

    5x10x0.1mm shims
    5x10x0.2mm shims
    5x10x0.5mm washers
    5x8x0.5mm fiber washers
    Go on ahead, I'm gonna take a breather.

  4. #4
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    Not uncommon at all. Manufacturing tolerances are at the core of the problem. .005 here, .025 there and it all adds up. You'll even run into this with identical hubs. I used to have two sets of wheels with Shimano XT 6 bolt hubs, identical rims, etc. One set for off road and one set for commuting. I had to use a .2mm rotor shim on the commuter set to get them to match up.

    Anyway, here's what you are looking for Universal Cycles -- Syntace 0.2mm Disc Brake Rotor Shims . My personal preference is for a shim that is specifically designed for a disc brake rotor. The full ring design supports the entire rotor flange once the bolts are torqued and make it less likely that you'll end up with unwanted noise or vibration. But individual shims will work.

    Good Dirt
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  5. #5
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    Cheap option in various sizes: Hope Shims | Buy Online | ChainReactionCycles.com
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  6. #6
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    Quote Originally Posted by Squash View Post
    Not uncommon at all. Manufacturing tolerances are at the core of the problem. .005 here, .025 there and it all adds up. You'll even run into this with identical hubs. I used to have two sets of wheels with Shimano XT 6 bolt hubs, identical rims, etc. One set for off road and one set for commuting. I had to use a .2mm rotor shim on the commuter set to get them to match up.

    Anyway, here's what you are looking for Universal Cycles -- Syntace 0.2mm Disc Brake Rotor Shims . My personal preference is for a shim that is specifically designed for a disc brake rotor. The full ring design supports the entire rotor flange once the bolts are torqued and make it less likely that you'll end up with unwanted noise or vibration. But individual shims will work.

    Good Dirt
    That's a nice find. I've bookmarked it for future reference. Can't positive-rep you anymore; so a public acknowledgement and a thumbs up.
    Go on ahead, I'm gonna take a breather.

  7. #7
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    Thanks for the info. Exactly what I was looking for!
    If you ever see a turtle on a telephone pole, remember he had help getting there. Is there anything beer can't do?

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