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  1. #1
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    Wishlist for future disc brakes...(ISO horny)

    First off, I love the stopping power of disc brakes and wouldn't think of going back to rim brakes, but...

    I think that our current systems need some work. I'd like to see:

    Pistons that retract fully and evenly. Many hydraulic systems have issues with this and the pistons don't stay centered. It seemed like Hope's old system of the internal return spring was a cool idea. It didn't work with an open, wear compensating design, but at least the pads retracted. I wonder if a similar idea could be worked into an open system.

    Pistons that retract further from the rotors. Rotors seem overly prone to warpage and it'd be nice if they didn't rub, even with a slightly wavering rotor. An extra 1/2 to 1 millimeter would be all it'd take. The caliper bodies would have to be slightly deeper to accomodate the extra piston throw. A way of 'servo-waving' the action at the master cylinder would be easy, allowing the pads to rapidly approach the rotor, then revert back to normal leverage for regular power and brake feel.

    And ISO caliper mounting really stinks. How did they think that was a good idea when they came up with it? For the life of me, I can't figure out how they decided on those numbers. Most calipers require an adapter with ISO or need to be shimmed for proper alignment... until your pistons refuse to center and you need to re-shim. And the leverage from running 200mm rotors up front is too much for many forks, mainly because ISO wasn't designed with large rotors in mind.

    I'm just crabby because I'm getting ready to build my new bike and can't decide what brakes to run. Hydraulics seem to be troublesome, yet I wanted to shave some weight by getting away from my trusty Avid mechanicals.

    I'd like to hear others' thoughts.

  2. #2
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    Hey you sound like an obsessed bike junkie like me. I love your thoughts and agree entirely. I was just thinkin tonight how stupid Shimano is to make such cool XTR hubs with splined rotor mounts. Come on. Don't they want to sell their hubs to anyone who currently use 6 bolt rotors? Oh I know, buy their hubs and expensive rotors separately. No thats dumb and expensive.

    Well anyway, I still think the best hydro brake this year will be the Avids. They align just like the mechanicals and have that nifty engagement adjuster. However at 331 grams a set I'm going to try the Magura Martas. Hope the setup and maintenance is not too difficult.

    They should design a caliper with more rotor clearance so rubbing even on a slightly warped rotor isn't an issue and like you said, come up with a better universal mount that doesnt require 1/2 a pound of adaptors or be so finicky to set up. Oh and of course all this at about lets say, 200 grams total weight.

    Wayno

  3. #3
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    shimano splined rotors are a ton better technically than 6 bolt rotors. It's stiffer, easier to replace rotors, no more stripped rotor bolts. the only, and i mean only, downside is that it's patented by shimano and hence $$$. but I think that if it was free, everyone would be using it now.

    -don

  4. #4
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    I have to say first that my expectations are influenced by the roadracing I used to do on motorcycles. I thougt the bike mfgrs have had a number of years to get the bugs ironed out, so you just choose based on who's got radial hand pumps, one-piece calipers, etc. and is making enough units to have tried and true stuff.

    Well, I guess I have to bring my expectations down a couple of notches.

    - I never had trouble mixing controls with brake levers on a roadracer. For some reason, I get the impression that a lot of MTB brakes have levers made on the assumption that everybody is now riding singlespeed, and there are no shift levers out there to get in the way.

    - I never had to use a special tool or milling machine to get brakes (even pretty garden variety ones) to bolt up to a fork or frame (and yes, the motorycle guys cast their stuff, too). And if it started to rain, you had to put in a different wheel with rotors, and guess what, there were no alignment problems.

    - No adapters, shims, etc. Those degrade the stiffness of the assembly and work directly against making the system light and stiff.

    What's on my current downgraded list?

    - Compatibility with a couple different lever types. The lever feel I prefer is different form someone who crushes Gerbils with their hands for a living (but he wants a brake for him, too). I want to tune the ratio of the lever to caliper pistons to suit me. And maybe there's a lever out there which doesn't interfere with shifters.

    - Pad compatibility. Before I choose my next brake I'm going to research who's making good pads, what the pad area is, etc. and choose a brake that fits them.

    - Fluid compatibility. Mineral oil is a nice idea, but if that means the manufacturers get to tune their products so that it only works with oil pressed by them from virgin newts during a full moon, I'm going DOT next time. That stuff you can get anywhere, cheap.

    What's on my wishlist?

    - Function. The brakes on the motorcycle could eat up a substantial portion of the energy in 2 gallons of premium gas in a quarter of an hour. And they do that with one or two fingers, no fading, if need be for hours.

    - Mounting. No shims, no adapters, no machining.

    - Standard fluids.

    - Pad choices. For the most part, the only thing you had to specify on the motorcycle was stainless or cast rotors. Then you got to choose a pad based on performance, service life, price, etc.

    - Almost forgot caliper piston travel. Because it really shouldn't be an issue.

    I get the impression it's like the fork thing all over again. People are buying discs because they're deciding they work better, just like they figured out that suspension forks are better than rigid ones. And they expect the kind of weight/performance we had with thin stanchions, elastomers, etc. I bet Fox knew how to build a fork back then, but no one would have bought it. Too heavy, overdimensioned, overpriced. I venture to guess that in general, brakes will get a little heavier, a little more expensive, and a lot better, once people figure out what they really want.

    Maybe I've got wierd views, but at least I feel better now having written that.

  5. #5
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    Dave

    you talk mucho sense.....

    'disc brakes will have to get heavier to get better' ......that's why nobody's put springs in to retract pads properly etc. but I think they will in order to produce a better functioning product.

    I mean you don't often get squealing car discs or rubbing ones for that matter..... how hard can it be to copy/scale down car brakes? ..... it's just the weight/cost factor causing the limitations at the mo........Avid are moving in the rigth direction though with the Juicy.

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