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  1. #1
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    Rotor bend on braking, is this normal;

    Hi, I just finished building my first ever hardtail with a set of Avid Juicy 7 2007 brakes with 160mm rotors. After a few rides and a wrong pad alignment on front making an annoying noise, now the brakes are perfect. Great power and no grab at all.
    Yesterday on a close inspect by viewing both rotors from above so I was looking just the rotor's thickness, when I applied power on brakes I saw that the rotors were bent slightly from pad pressure. When I released brakes the rotors went back straight again.
    Obviously the rotor thickness is as low as possible to save weight, but is this bend normal;

  2. #2
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    It means (most likely) that your pistons/pads are not properly aligned. When you apply the brake one pad hits the disc first and pushes it towards the other; hence the 'flex' you can see. When both pads hit the disc at the same time, as they should in a properly set up brake, there will be no flex.
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    What luck for rulers, that men do not think - Adolf Hitler

  3. #3
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    Thank you.
    Yes, I noticed that one pads touches first and pushes the rotor towards the other pad.
    I thought this was normal and disc bends due to minimal thickness.
    I aligned the calipers through the CPS bolts and I don't have any drag, but if you say that both pads should touch at the same time the rotor, I will realign calipers again.
    Many thanks again

  4. #4
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    You need to get the pistons aligned and working equally - the Avid CPS fails to ensure that this happens. Check out the caliper set-up and piston centralising videos on Hope's tech page (link). You may not be able to use the exact same method for centralising the pistons, but it'll show you what you're aiming for; then you just need to get creative. For example, if you have an assistant you can hold grab the disc with both hands and push/pull it against one piston while somebody pulls the lever to extend the other. Trial and error with this method will also allow you to get both pistons/pads working equally. Check out the videos, though; they clearly describe how best to align a caliper.
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    What luck for rulers, that men do not think - Adolf Hitler

  5. #5
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    A BIG thank's!
    I will try in the afternoon.

  6. #6
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    Quote Originally Posted by SteveUK
    You need to get the pistons aligned and working equally - the Avid CPS fails to ensure that this happens. Check out the caliper set-up and piston centralising videos on Hope's tech page (link). You may not be able to use the exact same method for centralising the pistons, but it'll show you what you're aiming for; then you just need to get creative. For example, if you have an assistant you can hold grab the disc with both hands and push/pull it against one piston while somebody pulls the lever to extend the other. Trial and error with this method will also allow you to get both pistons/pads working equally. Check out the videos, though; they clearly describe how best to align a caliper.
    Thanks to you now I have a perfectly straight on braking set of rotors. Powerfull too and dead silent.
    It took me around half an hour of tries but it worth it. It reminded me when trying to perfectly align my Denon DL304 cartridge on my turntable arm. I only used my eyes, my hands to move the caliper and a 5mm allen key to loose and tight the CPS bolts. Basically the most usefull tool is a pair of good eyes!
    Thanks for one more time!!!

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