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quality of brake discs...does it matter?

RamanujanRamanujan Posts: 352
edited May 2013 in MTB workshop & tech
Hi,
I've had my first set of disk brakes for a few months now (Avid BB7's)
At first I had some cheap 160mm shimano disks and the stopping power was hardly any better than caliper brakes (I use them exclusively on the road). I was so disappointed with them that I got a pair of 180mm disks (again cheap-ish Shimano ones) and they are a hell of a lot better and stopping power is great. However no matter what i do I can't get them to stop squealing (yes, I've tried everything).
I was wondering what the advantages are of better quality disks? If I paid for better quality disks would I get better stopping power and quieter braking?

thx!

Posts

  • guandaxguandax Posts: 44
    In my experience squeaky brakes have always been down to contaminated rotors or pads. I now always remove my wheels or cover the rotors with Tesco bags when using aerosol/spray oil. There are a few good articles worth reading in Tech FAQ section such as http://www.bikeradar.com/forums/viewtopic.php?f=40073&t=12674934 and http://www.bikeradar.com/forums/viewtopic.php?f=40073&t=12666026

    Good luck.

    Al
    Canyon Spectral 7.0ex 2015
    Giant Trance X3 2011 (retired but not sold!)
  • cooldadcooldad Posts: 32,904
    Simple answer - no.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

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  • Chunkers1980Chunkers1980 Posts: 8,035
    Not really to actual power, but holes ect can effect them as well as heat disputation
  • cooldadcooldad Posts: 32,904
    But Shimano are good quality, and have plenty of metal - unlike some expensive blingy lacy things.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • thelonegrooverthelonegroover Posts: 1,073
    I had a bike with Avid BB7's, they didn't squeal at all, however, another bike with Avid Elixir 5's did. No matter what I did I couldn't stop them squealing. I think my current Shimano Deore brakes are much better.
    Planet X Kaffenback 2
    Giant Trance X2
    Genesis High Latitude 2x10
    Planet X n2a
    Genesis Core 20
  • The RookieThe Rookie Posts: 27,747
    The avid CPS washer system reduces the mounting stiffness and makes them more prone to squealing, my old Juicy's used to howl like a Banshee when I had my lightweight alligator disc, swapping to a stiffer disc stopped it, when I went to a shimano IS mount caliper (so much stiffer mounting) I can fit the alligator and it makes no noise.

    I do not believe (nor has anyone been abled to explain why it does in a way that then stood up to interogation) that contamination makes a disc brake squeal, a squeal is something resonating at it's natural frequancy, sintered pads are worse than organic (organic having more hysterisys and act like a damper).

    Squealing can be made worse by badly aligned calipers or pads not worn 'square'. Avid BB7's usually give excellent performance when adjusted correctly, as good as most Hydro's.
  • cooldadcooldad Posts: 32,904
    Not often I agree with cyd but...
    My theory on brakes in general is that people fark around with them too much. Give them a rinse with a hose now and then, change pads as required, otherwise just leave them alone.
    My current ones on my main bike are 5 years old, never needed anything other than new pads.
    Couple of Shimano sets - replaced fluid after 5 or 6 years of hard use on one bike. Never touched the other.
    Some 10+ yr old Hopes - one fluid change although not used much now.
    Just leave them alone, they squeal sometimes - ride them, hose them, it goes away until it comes back and goes away again. Etc.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • thelonegrooverthelonegroover Posts: 1,073
    I'm not quite sure you are correct. I notice the frequency of the squeal stays the same but it's the volume that changes as speed changes. Disks squeal because the relevant frequency has been reached, the squeal gets louder because the amplitude increases not the speed. You could try installing some thin gasket type material between the disk and the wheel. Or install slightly thicker or thinner disks.
    Planet X Kaffenback 2
    Giant Trance X2
    Genesis High Latitude 2x10
    Planet X n2a
    Genesis Core 20
  • The RookieThe Rookie Posts: 27,747
    Sound frequency is unrelated to speed as it's something reaching it's resonant (not relevant!) frequancy.....
  • GiraffotoGiraffoto Posts: 2,078
    Didn't we have this conversation some time ago, and in the same circumstances (guy asks a question, gets it answered straight away, thread turns into a long running debate over what makes disks squeal)?

    Relevant stuff:
    Ramanujan wrote:
    If I paid for better quality disks would I get better stopping power and quieter braking?
    cooldad wrote:
    Simple answer - no.
    and . . .
    cooldad wrote:
    My theory on brakes in general is that people fark around with them too much.
    Specialized Roubaix Elite 2015
    XM-057 rigid 29er
  • thelonegrooverthelonegroover Posts: 1,073
    Some members like to expand and elucidate sometimes. Agreed, the simple answer may well be ‘no’ however some things aren’t quite as black/white or yes/no.
    Planet X Kaffenback 2
    Giant Trance X2
    Genesis High Latitude 2x10
    Planet X n2a
    Genesis Core 20
  • The RookieThe Rookie Posts: 27,747
    lon 456 wrote:

    So it says contamination with no explanation how....like I said, doesn't stand up to interrogation.

    And I did all it said, no difference with the Juicy's, and I once worked on a car where you could get the brakes to howl like you wouldn't believe, small mass added by the brake supplier (Brembo) to the pad and they were silent as church mouse.....it's all about resonances, because Avid aren't going to admit they will squeal by design are they?
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