Can't lock the rear brake

Anonymous
Anonymous Posts: 79,667
edited October 2012 in MTB workshop & tech
Hey guys.

Just got me bike in living room doing odd bits getting ready for some winter action.

I have been wanting to ask this question for ages, recently I went all 'weight weeny' .. I think we all need to get it out of our system at some stage :lol: :oops:

Anyway I upgraded the disc and the pads at the same time, but since doing this I have never been able to lock the rear and braking isnt as sharp as it used to be :shock:

I am not sure if its a brake line issue ? or the pads or even the disc ?

The pads I put on was the UberBike Sintered Brake Pads (Gold) – Hard Compound - http://www.uberbikecomponents.com/view- ... Brake-Pads

The disc is Ashima Light Weight AiRotor Double Ground 410 Stainless 160mm -
http://www.wiggle.co.uk/ashima-6-bolt-1 ... Air_Rotors

Is this going to be a process of elimination or can I rule out discs and go straight to pads ? I guess cheapest first ? and if its pads I need to look into first, can anyone suggest any good pads out there.

Thanks in advance :D

Comments

  • nicklouse
    nicklouse Posts: 50,675
    might just need a bit more bedding in.

    lever feels fine?

    not been spraying anything on or near your bike?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Great Ayton
    Great Ayton Posts: 337
    Hmmm. Has the lever feel changed at all? Metal bads do require a bit of bedding in but if this was the issue it should have sorted it self out on its first good ride. I have found the air rotors a little lacking in power but it should not effect you as much as you are getting. Is your bike making any strange sounds? Its possible you have got some sort of oil or something on the brake parts when fitting them?
  • Anonymous
    Anonymous Posts: 79,667
    Thanks for the reply guys.

    Well I have been riding and dragging the brakes wondering if they needed bedding in, I have been doing this for weeks now and still they not biting hard enough.

    Both front and lever feel fine as always and about an inch of travel until its rock solid.

    I have been spraying yes, what was it ... erm... oh that muc off cleaning stuff, but that was a while ago and as I said I been dragging the brakes for a while and its still not biting hard enough, unless its possible to contaminate the whole pad and render it useless ? I just dont know.

    I do have 2 new set of the same pads, maybe if I swap them over is there any way I can test to see if I had contaminated my pads that are in the bike ? i.e. will 1 x 20 mile ride xc enable me to lock the rear.

    Thanks :D
  • Great Ayton
    Great Ayton Posts: 337
    Try the other set of pads is your best bet. Though I would recommend getting some alcohol pads to clean off the rotor and caliper. Believe it or not they work much better then commercial brake cleaners. isopropyl alcohol or ethanol alcahol is your best bet.
  • Anonymous
    Anonymous Posts: 79,667
    I have just that Ayton, a giant tin of Isopropyl Alcohol, so I'll give the discs a wipe down and bang a new set in, i'll update this post if it solves it :)
  • adesaxo31
    adesaxo31 Posts: 88
    Did you clean the new disc before you fitted it it may have had oil or machining fluid on it
  • The Rookie
    The Rookie Posts: 27,812
    Wow that Ashima is heavy, the Alligators come in 3g lighter.

    Sintered and lightweight discs often means squeal, you have been warned.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • 70\ʹspenguin
    70\ʹspenguin Posts: 957
    Its either contaminated pads and a greasy rotor or too many pies! ;)
  • Anonymous
    Anonymous Posts: 79,667
    Yes I cleaned the discs before hand, pies now then, I ate a few of those buggers recently, and then some :lol:
  • mrmonkfinger
    mrmonkfinger Posts: 1,452
    CubeCrazy wrote:
    Well I have been riding and dragging the brakes wondering if they needed bedding in, I have been doing this for weeks now and still they not biting hard enough.

    A perfect way to glaze the pads. I'd suggest removing the pads, sanding the top layer off, and bedding them in properly - which basically involves pulling a number of hard stops, ie the opposite of what you have done.
    Blog
    Iron Horse Ojiki
    Carrera Kraken
    The Carrera Hardtail owners thread
  • supafly1982
    supafly1982 Posts: 631
    mrmonkfinger wrote:
    CubeCrazy wrote:
    Well I have been riding and dragging the brakes wondering if they needed bedding in, I have been doing this for weeks now and still they not biting hard enough.

    A perfect way to glaze the pads. I'd suggest removing the pads, sanding the top layer off, and bedding them in properly - which basically involves pulling a number of hard stops, ie the opposite of what you have done.

    aye, sounds like you have polished them, get emery cloth and take the glaze off. also do discs in a circular motion. wipe with IPA. then bed them in with fast hard stops. some pads need harder faster bedding in than others
  • Anonymous
    Anonymous Posts: 79,667
    Lovely guys thanks a lot for that I'll get on it :D

Categories