carbon wheel braking surfaces - whats normal?

paul_mck
paul_mck Posts: 1,058
edited June 2015 in Workshop
my full carbon wheels were starting to squeal a bit and I was getting burning smell after some sharp braking so checked the brake tracks and they were fairly well glazed up. got some scothbrite and roughened them up a little to take the glaze off.

noticed though that the resin has some small pock marks which Im a little concerned about.

Any thoughts? They are unbranded wheels, not sure on make.

Cheers.

2015-06-22%2019.32.47.jpg~original

Comments

  • jgsi
    jgsi Posts: 5,062
    Are you using carbon specific brake pads..?
    These are my FFWDs used in racing this and last season as a contrast.. not really any marking at all on the brake track.
    oynTLWS.jpg
  • paul_mck
    paul_mck Posts: 1,058
    yeah swisstop yellows
  • jgsi
    jgsi Posts: 5,062
    did something catch in them you reckon whilst riding ?
  • paul_mck
    paul_mck Posts: 1,058
    both sides of both wheels are like that most of the way around (maybe not so bad, but there).

    remember Ive just scuffed the surfaces up with scotchbrite, the area pictured I ran over with a wet finger to show up the pock marks better.
  • jgsi
    jgsi Posts: 5,062
    I'd go on the side of they still sound if a bit unsightly...they look like clinchers? just keep a watch over them.
    If in any doubt just check the rims for your own peace of mind.
  • paul_mck
    paul_mck Posts: 1,058
    yeah clinchers, I dont think they are a problem myself but worried in case the resin was overheating and coming apart or something but would seem odd to happen on all 4 surfaces at much the same rate.
  • sungod
    sungod Posts: 16,556
    given that you say they are the same on both wheels it's unlikely to be related to heavy wear as the rear typically gets little wear, for the same reason it seems odd to have glazed the rear

    looks a bit like they could be voids from the manufacturing process, if they're small and not concentrated in clumps then probably ok

    maybe the brake tracks simply aren't working well with the swissstop compound, you could try some different pads

    cork, reynolds, etc., or maybe swissstop black prince(ss claim lower temperature for the same braking force)

    btw i'd clean the brake tracks with isopropyl alcohol rather than abrasive, save any abrasive for taking the glaze off the pads
    my bike - faster than god's and twice as shiny

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