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  1. #1
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    Has there ever been a cable-actuated hydraulic brake produced for bicycles?

    I was having a conversation with a friend about different hydraulic brake designs, and the idea of a cable-actuated hydraulic caliper was brought up. (Hydra-mechanical?)

    I have owned a couple cars that had cable actuated (hydraulic) calipers in the rear (secondary for the parking brake) and it seemed like a simple and effective system. Cable pulls a lever, which in turn actuates a plunger/piston that pressurizes system and pushes pistons out.

    Wilwood makes a brake like this for DIY/Utility vehicle uses; http://www.wilwood.com/Images/Calipe...hanical-lg.jpg


    To me (non engineer obviously ) it seems like this type of design would be the best of both worlds; No Hydraulic hose/lines, less fluid volume, only one "unit" to bleed, and cheap/simple V-brake levers and cable could be used while having much greater power than typical mechanical disc brakes.

    Im assuming that this idea has been tried, tested, and shelved for a reason that I am overlooking... but what is it?

  2. #2
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    Cables are the weakest link in this system - hydraulic hose (brake fluid ) is much stiffer.

  3. #3
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    Rockshox first and last turn at disc brakes was cable actuated with a hydraulic piston.


  4. #4
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    Quote Originally Posted by vanamees View Post
    Cables are the weakest link in this system - hydraulic hose is much stiffer.
    Seems just as prone to damage/failure as a Hydraulic hose. And unlike Hydro hose, it can be serviced/replaced on the trail.....

  5. #5
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    Quote Originally Posted by SFBMRC View Post
    Rockshox first and last turn at disc brakes was cable actuated with a hydraulic piston.

    Wow. How far we have come in so little time! Thanks for the pic, very cool

  6. #6
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    Quote Originally Posted by Bobby12many View Post
    Seems just as prone to damage/failure as a Hydraulic hose. And unlike Hydro hose, it can be serviced/replaced on the trail.....
    I'm only guessing, but I suspect he was saying that the cable is the weakest link in regards to performance rather than damage. I don't have an opinion on the matter, but it does make sense that there is less loss of energy with fluid as compared to wire/cables/etc.

  7. #7
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    Hope have a system (V-Twin) for CX bikes that allows use of the standard brifter (ie mech) to actuate a hydraulic caliper. Closest thing I have seen in a while.

    I think that there are a few systems like this out there for CX at the moment. TRP Parabox?

  8. #8
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    There were a couple others too. Mountain Cycle had one (which I believe Rock Shox purchased the rights to) and so did Hayes. Problem they all sufffered from was heat. Having the master cylinder and reservoir built into the caliper proved to be a very unwise idea. None of the systems could cope with heat well.
    You are not what you own.

  9. #9
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    Quote Originally Posted by juancancook View Post
    There were a couple others too. Mountain Cycle had one (which I believe Rock Shox purchased the rights to) and so did Hayes. Problem they all sufffered from was heat. Having the master cylinder and reservoir built into the caliper proved to be a very unwise idea. None of the systems could cope with heat well.
    Now THAT is an aspect I didn't consider. Keeping all of the fluid entirely in the hottest part of the system probably isn't wise.

  10. #10
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    Quote Originally Posted by juancancook View Post
    There were a couple others too. Mountain Cycle had one (which I believe Rock Shox purchased the rights to) and so did Hayes. Problem they all sufffered from was heat. Having the master cylinder and reservoir built into the caliper proved to be a very unwise idea. None of the systems could cope with heat well.
    I think it might have been AMP disc brakes that RS bought the rights too but mountain cycles had their own prostop but it was one of the first hydraulic disc brakes available with an aluminum /steel floating rotor and mineral fluid. It was pretty far advanced for when it was available.

    The other issue with the cable actuated hydros was that unlike the pure mechanical lever that operates the piston in a modern hydro the cables that operated the piston were prone to stretch during actuation giving the caliper a mushy feel. Factor in cable housing flex, lever flex and cable guide flex and they were just plain mushy.

    Since cars have used remote calipers and reservoirs for ages it really doesn't make sense to rethink the system just to save an ounce or 2 of fluid weight. All in all it was a more complex system and obviously much more susceptible to heat issues as mentioned before.
    Try this: HTFU

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