Some issues with XT brakes- Mtbr.com
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  1. #1
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    Some issues with XT brakes

    Some issues with XT brakes

    I just got a pair of Xt Disc brakes and have some issues with the levers. It seems that for 60% to 75% of the lever movement has no brake action. The last 25% to 40% is when the brakes actually engage.

    What can I do to fix this?

    I checked out shimanos website and they only have pdfs for dismantling and how to bleed the brakes.

    Ideally I would like the brakes to make first contact with the rotor at about 10% into the lever movement and max brake power around the 65% to 75%. This is my first set of hydro brakes. Sorry if these are noob questions.

    Is my current function the norm for XT brakes?

    Will bleeding them help?

    Are there any other tips you can recommend to help me achieve what I am trying for.

    Thanks in advance for your help.

  2. #2
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    Ok I have done some online research. I found out that what I want to decrease is called the “free stroke.” I would like there to be less free stroke.

    On the lever itself there is a screw that you can tighten or loosen to find your best fit. I have noticed marginal difference between fully tighten and full loosened.

    Is there any other way to reduce the amount of free stroke in my lever?

    I found some random forum thread on a different site that was suggesting that I need to add more brake fluid?

    Before I mess with that I wanted to double check to see if that would even give me my desired result?

    Is this just the normal function of the XT brake lever?

    Thanks again for any help

  3. #3
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    This is normal behaviour of the brakes, it varies per brake type how much lever travel there is and some have a limited amount of adjustment available (like the screw on your XTs). You can trick earlier engagement by overfilling the brakes, but this is not a good/permanent solution and will force the pads closer to the discs (which cause more drag problems); it will not be permanent because the pad to disc clearance is determined by the used piston quad rings (which are key to the auto brake pad adjustment). In general, the amount of free stroke depends on: 1) the gap between pads and discs; 2) on the hydraulic ratio between master (the one in the lever) and slave (the ones in the calipers) pistons and 3) the mechanical leverage ratio (how much the master piston is moved by moving the lever). Stronger brakes are made by using higher ratios (same master with larger slave pistons most of the time) and thus more inherent free stroke. Shimano does do a clever trick to reduce this effect by changing mechanical leverage ratio over the range of lever travel. All in all from experience with XT, older Louises and Mono M4s I can say that XT and Louise do both have more free stroke than the Hopes; this is inherent to the design and cannot easily be changed (except for the limited adjustment allowed by the XTs).

  4. #4
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    Quote Originally Posted by kumarpr227
    What can I do to fix this?
    ...
    Will bleeding them help?
    Yes - do that.

    All my Shimano brakes have at max 33% free stroke.

    Tightening the reach-adjust screw only moves the at-rest position of the lever, and doesn't change the engagement of the pads at all.
    Last edited by forkboy; 05-18-2010 at 07:27 AM.

  5. #5
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    Thanks a lot for the tips. This is my first set of hydro brake. I think I was just too used to the way mech brakes felt. They were real easy to adjust the free stroke.

    I don't think I will bleed them myself. I will go back to the LBS I got them from and have them do it. I just sunk this money in and don't want to mess them up by trying to bleed them myself for the first.

    I think I will just ride around with them for a week or two and see if I can just get used to the new feel.

    Thanks a ton for the feed back guys.

  6. #6
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    Quote Originally Posted by forkboy
    Tightening the reach-adjust screw only moves the at-rest position of the lever, and doesn't change the engagement of the pads at all.
    Actually the latest 775 XT brakes do have two adjustment screws, the reach adjust is the tool free knob and a philips head screw allows some free stroke adjustment/bite adjustment.

  7. #7
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    The tool free knob just moves the lever closer or farther away from the Handlebars. Does nothing about the free stroke. The screw adjusts the free stroke but not by any huge marginal difference. Its noticable not near what I was hoping for.

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