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  1. #1
    Nerdy Jock
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    Why brakes lack power?

    I understand the basics of hydraulic disc brakes, but I don't understand how the amount if power and modulation varies so much between brakes that are fundamentally similar.

    These are the factors I can think of: rotor size, number of pistons, consistent and air free fluid, heat dissipation... And not much else.

    Approximately how much more braking power would a 160mm rotor have over 140? Or 180 over 160? 20% possibly?

    I'm thinking about all of this because my Juicy 7's just don't seem to have enough power and I can't think why.

    Thanks

    Sent from my fingers.
    Current bike: Rocky Mountain ETS-X 70

  2. #2
    mtbr member
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    Factors that affect brake performance....

    Brake pad composition

    Brake pad contamination

    Hydraulic mechanical advantage

    Brake hose expansion

    Rotor surface

    Rotor contamination

    Water contamination in brake fluid

    and....something that is seldom discussed, TIREs

    besides factors you already mentioned. Im sure there are more.

  3. #3
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    And piston diameter and the size of the ports the fluid flow through and the diameter of the master cylinder and......and...... You can go on for eons about factors but in the end it is how much it was desinged to have

    The percent change in the power due to rotor size is a basic calculation. 140/160 = _%, 160/180 = _% at least approximately

  4. #4
    Nerdy Jock
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    Quote Originally Posted by tyler243 View Post
    ... it is how much it was desinged to have
    Why would some brakes be designed to have less power? It doesn't seem to me like having larger ports would increase weight or do anything else negative. But there must be some downside.
    Current bike: Rocky Mountain ETS-X 70

  5. #5
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    Yeah having larger pistons and higher flowing ports doesn't add much weight if any but its is all about making money, why would they sell a bargain basement xc brake for $50 that has the same power as their $200 top of the line dh brake. Stupid yet its how they make money. Also I don't think youd aNy to start speccing saint level of power brakes on pave path brakes, can you say endo. I'm sure their are other factors but that is just why comes to mind

  6. #6
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    Quote Originally Posted by zaner123 View Post
    Why would some brakes be designed to have less power? It doesn't seem to me like having larger ports would increase weight or do anything else negative. But there must be some downside.
    Its about the design process. Nothing ever works out as designed. It can comes close, it can fall short, or exceed expectations big time. Complex systems can be quite unpredictable. Excellent products are the product of one of two things, relentless design improvement, or years of experience.

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