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  1. #1
    I Tried Them ALL... Moderator
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    Hydros - Constant Rotor Friction?

    I am a longtime BB7 user, who is going to finally switch to hydros. From what I see- hydros need to have a plastic spacer inserted, when the wheels are removed,to prevent the pads from sticking completely together. I am not used to this, since my BB7 mechanicals have a comfortable gap between the rotor and pad surfaces. Does this constant pad contact on hydros mean constant, light friction, seriously affecting rolling resistsnce too? TIA....
    "The mind will quit....well before the body does"

  2. #2
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    Reputation: rkj__'s Avatar
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    Quote Originally Posted by Zachariah
    I am a longtime BB7 user, who is going to finally switch to hydros. From what I see- hydros need to have a plastic spacer inserted, when the wheels are removed,to prevent the pads from sticking completely together. I am not used to this, since my BB7 mechanicals have a comfortable gap between the rotor and pad surfaces. Does this constant pad contact on hydros mean constant, light friction, seriously affecting rolling resistsnce too? TIA....
    No no. The pads don't rub on the rotor when the brakes are not applied. But, if you squeeze the lever when there is not rotor there, the will over-extend, and not fully retract on their own. If the wheel is removed, and you never squeeze, touch, or accidentally bump the lever, the pads will stay in their retracted position.
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  3. #3
    I Tried Them ALL... Moderator
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    Quote Originally Posted by rkj__
    No no. The pads don't rub on the rotor when the brakes are not applied. But, if you squeeze the lever when there is not rotor there, the will over-extend, and not fully retract on their own. If the wheel is removed, and you never squeeze, touch, or accidentally bump the lever, the pads will stay in their retracted position.
    So what you are saying that hydros have this tiny 3mm or so margin of play, before over-extending......and require manual seperation of the pads?
    "The mind will quit....well before the body does"

  4. #4
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    pretty much.... ya.
    When under pressure, your level of performance will sink to your level of preparation.


    Shorthills Cycling Club

  5. #5
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    The retraction of the pads is controlled by the piston seals. The seals allow a certain amount of piston movement in and out. The seals themselves can move within the bore when pushed far enough. This is how brakes self-adjust for pad wear: as the pads get thinner, the seals move further and further out and maintain the same clearance to the rotor. By the same token, without a rotor or spacer in place, the pistons can be pushed too far and the pads will have to be pried apart by hand.

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