Magura rim brake questions

Discussion in 'Cycling Equipment' started by James Thomson, Feb 29, 2004.

  1. I'm interested in buying a Magura HS66 hydraulic brake. From the exploded diagrams I've found on the
    web, it appears that it would be possible to add a supplementary lever to each brake by connecting
    one lever to each slave cyclinder and linking the slave cylinders as normal. Can anyone confirm that
    this is the case?

    I'm also interested in general intercompatibility between rim brake models (I know that the disk
    brakes aren't compatible with the rim-brake levers). Are the various series of rim brakes broadly
    intercompatible?

    Thanks,

    James Thomson
     
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  2. jmm

    jmm New Member

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    > I'm also interested in general intercompatibility...

    James - Magura has used two different cylinder sizes in their hydraulic rim brake levers, 16mm and 14mm. They have used only one diamater on all of the slave cylinders.

    The current HS-11 and HS-66 use 16mm, and the HS-33 uses 14mm. The early (but no longer produced) HS-22s used 16s, then switched to 14s in later production models. Theoretically one can use either size lever cylinder, but you'd probably want to match sizes on a dual lever system. The 14mm cylinders develop a little more "power", at the expense of slightly less slave cylinder/pad travel.

    John
     
  3. jmm

    jmm New Member

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    >...it appears that it would be possible to add a supplementary lever to each brake...

    James - Your other questions intrigued me, so I checked out some of my Maguras after making the first response.

    If you're planning on connecting the 2nd lever to the "bleeder port" on the slave cylinder, there's a problem. The thread on that port is different (smaller) than the other three ports that accept hose fittings. So, you would have to retap it (might be difficult to get a good sealing surface), use two of the cylinders with two hose fitting sized ports, or "T" into an existing line somewhere.

    Also, I think it might be best to ask Magura if the seal or stop mechanism on the lever/cylinder not being used can withstand full "backwards" pressure in it's outermost position. An HS-66 lever may actually be better than an HS-33 in that respect, as it does not have "thumb adjusters".

    One other thing that might be best to avoid if you're going to be scrounging for levers/cylinders is the "composite" levers used on the HS-11 and some OEM systems. The metal ones are much better, from both a feel and durability standpoint.

    If you havent already found it, plug "Magura Cult" into Google, and check out that website.

    John
     
  4. "jmm" <[email protected]> wrote:

    > If you're planning on connecting the 2nd lever to the "bleeder port" on the slave cylinder,
    > there's a problem. The thread on that port is different (smaller) than the other three ports that
    > accept hose fittings. So, you would have to retap it (might be difficult to get a good sealing
    > surface), use two of the cylinders with two hose fitting sized ports, or "T" into an existing line
    > somewhere.

    Thanks for the input. It looked to me as though the link hose and bleeders use the same barbed
    fitting (the online service manual makes no distinction between the two) and therefore the same
    thread. The parts diagram on the Magura website labels the two slave units 'M6/M6' and 'M6/M8' which
    I'd interpreted as the threading.

    I'm not clear why the main hose and link hose use different fittings. Any idea?

    > Also, I think it might be best to ask Magura if the seal or stop mechanism on the lever/cylinder
    > not being used can withstand full "backwards" pressure in it's outermost position.

    Good point.

    > If you havent already found it, plug "Magura Cult" into Google, and check out that website.

    I had checked it out, but thanks for reminding me of it again. I found the information about master
    piston diameters, and a few other useful facts, though nothing directly related to using
    supplementary levers.

    I think maybe I should just get my hands on a set and start experimenting. I've found posts in the
    deja archive from an employee of Magura USA who says that this is not only possible, but "real
    simple to set up". Unfortunately, my emails to Magura are -so far - unanswered.

    James Thomson
     
  5. jmm

    jmm New Member

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    > The parts diagram on the Magura website labels the two slave units
    > 'M6/M6' and 'M6/M8' which I'd interpreted as the threading.
    >I'm not clear why the main hose and link hose use different fittings. Any idea?

    James - It almost seems that the designations you mention from the parts manual are backwards, at least by my way of thinking. It would seem to make more sense if they were M6/M8 and M8/M8, here's why:

    One cylinder has two of the "larger" tapped ports that definitely appear to be threaded the same. One port is for the barbed fitting on one end of the crossover tube, and the other accepts the hose from the lever, secured via a ferrule and compression nut. The male threads on a barbed fitting and lever hose compression nut appear to be identical, and I have switched the port that each of these goes to in the past, for "routing" purposes.

    The other cylinder has two different sized ports. The larger one is the same as both of the ports on the other cylinder, and accepts the barbed fitting on the other end of the crossover tube. The smaller port accept the plug screw that you remove to bleed the system, and that's the oddball one that I though you were going to try to connect a second lever to.

    By the way, I haven't used HS-66s, and can't remember whether they come with a booster (bridge). I thought some of the frames I've used Maguras on had pretty beefy stays and brake pivot bosses and therefore wouldn't need a booster. I was wrong, I haven't seen an installation yet that didn't benefit significantly from using a Magura booster, given the force that these brakes can develop (particularly the 14mm piston versions). I've used their steel, alloy and carbon fiber versions, and would say they all perform about the same, you just pay more as you move down the weight sacle.

    Also, I've been using Magura "Red" compound pads lately, wet or dry. It is my understanding that these are made by Koolstop for Magura, and certainly appear to be the same as the Koolstop "Salmon" pads I was using in all my V Brakes before switching to Maguras.

    Have fun tinkering if you go for it. These are truly great brakes when set up properly.

    John
     
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