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  1. #1
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    How do i measure the "reach" for brake calipers when converting from 27 to 700c?

    On the schwinn I'm fixing up, I am rather pondering possibly converting to 700c. At first i wasn't going to but now I'm thinking again I might want to.

    The thing that is confusing is how do i measure the caliper reach so I can get the proper replacement calipers in there?

    Currently the bike has a set of sidepull single pivot sidepulls and the front one is rather bent up. Even if I do not convert to 700c, I still would like to convert to double pivot caliper brakes but I'm not sure how to measure the calipers to get the right size, standard or long reach.

  2. #2
    coprolite fietsbob's Avatar
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    reach is the distance between The place where the brake is mounted
    a horizontal line
    to the top and bottom of the mounting slot for the brake-shoes.
    a vertical perpendicular, 90 degrees, off the horizon line.

    centers of bolts,holes, is the place dimensions are taken as standard practice.

  3. #3
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    + 5 mm? Check out tektro, they might have what you need.

  4. #4
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    Okay, so i should mount the 700c or 27 inch wheel and measure like the following picture:
    Attached Images Attached Images

  5. #5
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    And in reference to the above picture, I have not cold set my frame to allow for the 130 spacing of a more modern road hub but I can safely assume that if I measure with my existing 27 inch wheel in place, I could add 4mm and be within a safe range for the caliper for a 700c wheel?

    in other words, I want to measure the distance like the above picture and look for a caliper that has my measurement within the specs of the caliper. So if I measure 38mm, I want to look for a brake that might have a reach of 35 to 40 mm or whatever spec is available. And if I am thinking of converting to 700c, add 4mm to the overall measured reach so it would then be 42mm as an example if I do decide to convert to 700c.

  6. #6
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    Quote Originally Posted by bobotech View Post
    And in reference to the above picture, I have not cold set my frame to allow for the 130 spacing of a more modern road hub but I can safely assume that if I measure with my existing 27 inch wheel in place, I could add 4mm and be within a safe range for the caliper for a 700c wheel?

    in other words, I want to measure the distance like the above picture and look for a caliper that has my measurement within the specs of the caliper. So if I measure 38mm, I want to look for a brake that might have a reach of 35 to 40 mm or whatever spec is available. And if I am thinking of converting to 700c, add 4mm to the overall measured reach so it would then be 42mm as an example if I do decide to convert to 700c.
    Correct and correct.

  7. #7
    Senior Member Bill Kapaun's Avatar
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    Theoretically, it's 4MM.
    It might vary a little bit depending on the "angle" of the rim braking surface and/or width of the rim.

    I swapped on a 700C wheel to an old 10 speed last summer and only had to move the pads about 2MM in the slot.
    I have to admit that I didn't check pad alignment to the old wheel first, so maybe they were already a bit too far toward the spokes???

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