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  1. #1
    mtbr member
    Reputation: Johnny Chicken Bones's Avatar
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    More specific XTR v XT questions...

    Yup, I've searched, nope- no conclusive answers.
    As far as I have found- the 08 XT disc brakes are thought to be stronger (20% claimed) versus the latest gen XTR. Am I right that this is a result of the lever design (servowave) only? The added strength doesn't come from caliper differences?

    Second- The servowave idea goes back a ways w/ the Shimano folks. If I understand it correctly: It is set up for alot piston (or v canti pad) travel early in the lever pull, and short but powerful piston travel as the pads contact the rotor.
    So the question is- at the point of pad/rotor impact do the XT lever putting more PSI down than the XTR levers?

    In fact, now that I think of it we could determine what sort of PSI each brkae puts out per pound of lever pull. After that it would get hazier w/ the introduction of pad material and size. Still, it would tell us if a new design was really that different from last years greatest.

    Yes. they are dorky questions. This is what our record snow year has done to my brain.
    Thanks.
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  2. #2
    Meh.
    Reputation: XSL_WiLL's Avatar
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    According to Shimano, the new lever does increase pressure. They had recommended against use with a 755 because of the potential for the seal to fail under the higher pressure.

  3. #3
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    Interesting. I'd always heard that all shimano disc levers were compatible w/ all calipers. It'd take a bit but I thought I read it on their site under the tech info. Course, that was before the newest 08 XTs were out. Thanks
    --------- __o
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  4. #4
    Nightriding rules SuperModerator
    Reputation: crisillo's Avatar
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    Quote Originally Posted by XSL_WiLL
    According to Shimano, the new lever does increase pressure. They had recommended against use with a 755 because of the potential for the seal to fail under the higher pressure.
    interesting..that is a little known fact indeed...I am running the 08 levers with my 765 caliper now too...but it might be an issue with the seals of the 755s (I guess)...

  5. #5
    Meh.
    Reputation: XSL_WiLL's Avatar
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    I guess they figured something about age of the caliper... amount of use... all that... I don't know. I know they have been paired successfully to the 765. And there had been a member on the board that was going to match them up to 755s.

  6. #6
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    Hi johnny chicken bones,

    I've copied your question directly and posted it to shimano as i am super concerned abt what you asked too

    guess wat,... and they replied me

    Hi Kk,

    Thanks for your inquiry. You are correct in all of your comments. The 20% boost in power is dueto the ServoWave brake lever design. Just like the original ServoWave,you get a lot of pad travel early in the stroke, then short travel +high leverage as you pass through the stroke. Use of ServoWave brakelevers (like XT) will result in more clamping pressure at the pad, butI don't have a PSI figure. Yes, XT08 ServoWave levers are 100%compatible with XTR M975 calipers.

    Best regards,
    Greg

    Cheers,
    KK

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