Magura mdr-p floating rotor loose- Mtbr.com
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  1. #1
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    Magura mdr-p floating rotor loose

    I have a magura e-stop 220mm floating rotor disc on e-bike and noises clack on floating pivots, the movement is visible with only 150 km, can't be right, isn't it?

    https://www.magura.com/en/components...lpage/?p=49049

  2. #2
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    Seems to be normal a bit of movement but here is the video with 150km, just raise volume up, scary at least.
    https://drive.google.com/file/d/1x8s...ew?usp=sharing

  3. #3
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    What do you think "Floating" means when describing floating rotors?

  4. #4
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    Quote Originally Posted by Taildragger View Post
    What do you think "Floating" means when describing floating rotors?
    I don't need to think and argue about floating discs, have you seen the video? So you says it is a normal behavior on 150km wear? I'll be relieve if yo can assure it but I'll wait for magura answer also.
    No one with mdr-p rotors around?

  5. #5
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    I had high performance track motorcycles with floating rotors that rattle when pushing the bike at walking speed. Absolutly no problems. Btw, why so defensive?

  6. #6
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    I had some cheap chinese pinned rotors at one point that did that, it made riding pretty terrible, because there'd be a significant force transmitted when I started braking, kind of like a fork crown creak. Not acceptable. I spent a while trying to track down the problem. I also had hope floating rotors a few years before that and they did NOT do that. The point of pinned rotors (sometimes referred to as "floating") is to allow the outer braking surface to expand at a different rate than the aluminum carrier, thereby not warping. Again, play is not acceptable with these in my experience. Most of my rotors these days are 2-piece, no play.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

    You're turning black metallic.

  7. #7
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    Quote Originally Posted by Taildragger View Post
    I had high performance track motorcycles with floating rotors that rattle when pushing the bike at walking speed. Absolutly no problems. Btw, why so defensive?
    In what direction?

    https://ebcbrakes.com/articles/the-f...tually%20float.

    90% of rotors branded as floating types are actually simply a two piece rotor where the outer rotor ring is riveted to a central hub by circular mass produced rivets. A rotor made with circular rivets does not float at all because the tolerances (differences in PCD – pitch circle diameter of the inner and outer components) would need to be so large that the rotor would rattle and shake from day one. At this point it is essential to differentiate between axial floating and radial floating. Any motorcycle rotor built with axial float often described by people as a self centering rotor is also doomed to failure. The pad and piston knock back effect of a rotor with axial float is simply a killer and causes sponginess and can render brake levers coming right back to the motorcycle handlebar when trying to re-connect the “knocked back” pad with the rotor under braking. Not good at all!

    So zero axial float is needed or desirable in any type of rotor.

    Under braking and heat generation the outer ring or rotor blade of every two piece motorcycle rotor suffers from band width growth, in other words the outside of the rotor grows outwards but the inside SHRINKS inwards. It is this shrinking inwards that defeats the myth that two piece rotors actually float.

    Imagine how the outer ring and inner hub behave having a tiny tolerance over the circular rivet (to avoid rattle). The rotor ring shinks inwards, hits the circular button, locks up and then, unable to go anywhere, the rotor warps or distorts.

    So there are two ways to go from here 1) increase the tolerances between the rotor ring hub and circular rivet or 2) change the rivet design.

    That is where the EBC patented SD-System (standing for Square Drive) comes in.

    As shown in the photographs top- left, the rivets connecting the outer rotor ring and the inner hub both have parallel sided slots in them and the rivet is also made with flat sides that connects the two parts of the rotor and generates LINE CONTACT as compared to POINT contact allowing the rotor ring to expand and contract without binding during the heat of braking and cooling.

    Here we get a perfect line contact between all the components that allows the rotor to freely expand the few thousandths of an inch that are all critical without any “Locking up”.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

    You're turning black metallic.

  8. #8
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    Oh yeah, and my car has 2-piece "floating" rotors. They don't knock.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

    You're turning black metallic.

  9. #9
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    Quote Originally Posted by Jayem View Post
    Oh yeah, and my car has 2-piece "floating" rotors. They don't knock.
    The magura's are bit different than the standard floating rotors, seems to "touch" not only on pivots, but also on all "big thoot", the problem is the tolerance is more than a millimeter right now, so what will be the play with 15000 km? let's see what are the acceptable tolerances by the manufacturer.

  10. #10
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    Quote Originally Posted by edge540T View Post
    Seems to be normal a bit of movement but here is the video with 150km, just raise volume up, scary at least.
    https://drive.google.com/file/d/1x8s...ew?usp=sharing
    I'm using these rotors and that movement is normal and expected with this design.

  11. #11
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    Eh, true floating rotors vs semi-rigid floating rotors. Pleas keep us informed as to what Magura has to say about it.

  12. #12
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    Yeah, that movement is what my cheap chinese floating rotors did. To be fair, not all at once, it took about 6 months or so, but at that point, it was scary braking and that knocking transmitted into a pretty forceful "bump" when you were getting on the brakes in tech terrain. You always felt it transmitted to the bars and your hands/arms. It is NOT a good feeling and it is NOT the way brakes should work. Anyone that says this is normal is crazy IMO.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

    You're turning black metallic.

  13. #13
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    Quote Originally Posted by springs View Post
    I'm using these rotors and that movement is normal and expected with this design.
    oh .. nice, yesterday I have an insight that could be normal, after the process to find where the sound came seems a nasty joke, let's see if the design produces this clack sound, may be on other forks-caliper-bike is not so loud.

  14. #14
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    FWIW: I haven't followed all of the posts but here's a pic of the floating front rotor on my moto. The rotor and carrier to not touch and are held in the same plane by the large hollow rivets. My previous moto had a similar setup but with wave washers under the heads of the hollow rivets. I could get the previous one to click when the rotor moved with respect to the carrier. The current one doesn't click.

    Magura mdr-p floating rotor loose-20200802_104302.jpg
    What, me worry?

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