New brakes set up, front pads missing part of rotor sweep

abarth_1200
abarth_1200 Posts: 370
edited May 2014 in MTB workshop & tech
Couldn't find anything through search about this.

New rotors, shimano adapters and xt brakes. Quick spin and I can see from the wear on the rotors that the front pads are overlapping the rotor as it sweeps round. Rear pads are dead in the middle.

Rear
C87956D8-4FFD-4672-9B0C-D17D04EAC730_zps5btncbmi.jpg

Front
1C7D223B-812B-443A-A2D5-62D04CEA52BF_zpshghlbtah.jpg

Only thing I can think of is facing the front post mounts on the forks, but they appear to have been done already.

Comments

  • poah
    poah Posts: 3,369
    look at the pads, shimano OE have a slant at the end so don't hit the whole rotor. 3rd party pads don't have this

    shimano-xtr-br-m985-brake-pad-sintered-brake-pads-1-a_1.jpg
  • abarth_1200
    abarth_1200 Posts: 370
    Yeah but even still the fronts upper edge (outermost edge) is missing the rotor completely, like the adapter is too big.

    I'm wanting to get the best performance out these brakes but if the pad is missing the rotor it's obviously not getting full contact and I can see wear problem further down the line.

    You can see from the pics the rear has a couple mm either side of the pad contact area but you cant see the edge of the front pad contact area.

    Thanks
  • poah
    poah Posts: 3,369
    sounds like the rear adaptor is either made wrong or on the wrong way?????????
  • abarth_1200
    abarth_1200 Posts: 370
    The rear pad contact area is correctly covering he whole of the rotor with a margin either side.

    It's the front with the issue.

    Do you guys want a pic of the front and rear calipers too?
  • cooldad
    cooldad Posts: 32,599
    So maybe the front adaoter is upside down.
    I don't do smileys.

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  • abarth_1200
    abarth_1200 Posts: 370
    th_e232a468aefa321fa16cbc4a158ebcdc_zpsc4815edd.jpg

    th_1659f0f8294a9907006ec83628400855_zpse940870b.jpg

    Looks right to me but just for the people in doubt
  • poah
    poah Posts: 3,369
    front looks like mine, rear looks wrong.
  • abarth_1200
    abarth_1200 Posts: 370
    How, it's got an arrow on the adapter pointing up, and it's the same way according to the instructions.

    Find me another pic of an xt caliper with is mount frame and 180mm rotor.

    Hang on search in google

    shimano xt caliper on frame

    And see first image of pads worn halfway through which I think will happen to my FRONTS.

    The adapter is the right way round, scroll through the rest of the pics and see similar is mounts.
  • ricardo_smooth
    ricardo_smooth Posts: 1,281
    Both adapters are fine. If it was me, I'd try re aligning the calipers. Maybe it's moved down when tightened, so it could be centred, but sitting too low. What are the gaps like fore and aft of the caliper to the disc?
  • nicklouse
    nicklouse Posts: 50,675
    Not a problem. For some reason many set ups are like this don't worry about it.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • abarth_1200
    abarth_1200 Posts: 370
    Thanks for seeing that the adapters aren't the problem.

    There's not much room for it to move down, there's only really movement left and right.

    I know what you saying nicklouse but would I be able to file down a bit off each post on the forks or is this a bike shop job and the proper cutting tool. I just don't want the pads to end up wih a chunk of material gouged out them rubbing along the edges of these aluminium and steel rotor sandwiches
  • heez29
    heez29 Posts: 612
    Is the pad in full contact with the disc though?

    Try the adaptor the other way around?
  • abarth_1200
    abarth_1200 Posts: 370
    From the wear marks on the machined rotor surface I would so yes it is in full contact, on the parts that run through the line of the pad area.

    Other way round, as in turn it upside down or use it back to front, I don't think it will work back to front as the bend in the adapter is there to make room for the caliper. I could however fit it upside down and see if that helps, but it's not the right way of doing things. I'll it tomorrow anyway to see
  • nicklouse
    nicklouse Posts: 50,675
    Thanks for seeing that the adapters aren't the problem.

    There's not much room for it to move down, there's only really movement left and right.

    I know what you saying nicklouse but would I be able to file down a bit off each post on the forks or is this a bike shop job and the proper cutting tool. I just don't want the pads to end up wih a chunk of material gouged out them rubbing along the edges of these aluminium and steel rotor sandwiches
    They won't.

    You are worrying over nothing.

    Many set ups have been like this for years and work just fine.

    If you really want to remove some material you could try and find a bike shop with a milling machine, very rare, or find a engineers work shop and tell them how much to take off the adaptor, don't take the bike.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • abarth_1200
    abarth_1200 Posts: 370
    Alright I'm convinced I'll leave it alone, after all it's not the end of the world if my pads don't wear evenly, as long as my brakes work to their full potential.

    But yeah good point don't take the bike lol, milling shop would only need the adapter.

    Thanks br!