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Why are my pads shredding my rims all of a sudden?

peatpeat Posts: 1,243
edited January 2015 in Road general
I've never had this issue before, but this winter is killing my rims.

The blocks seem to be picking up tiny metallic lumps (presumably of the braking surface) every ride. I pick the pads clean with the tip of a scalpel and within 2 or 3 uses of the brakes, the wince-inducing noise of metal on metal is back.

Are my rims falling apart? Or are my pads over-worn?

Cheers

Posts

  • Bar ShakerBar Shaker Posts: 2,313
    It is most likely bits of sand and silt in the pads.

    I lightly sand mine clean every few rides.

    Toeing them in slightly so the rear edge of the pad touches first will help keep the main contact area clean.
    Boardman Elite SLR 9.2S
    Boardman FS Pro
  • SmithsterSmithster Posts: 117
    Maybe this winter is just a bit wetter enabling grit to be picked up easier. I only have one bike, but this year it seems to be getting more hammer than last year. My wheels too are also getting trashed.
  • How long have you had the wheels for?
    When my original set wore out in the wet last winter their wear seemed to accelerate near the end in a kind of vicious cycle. That could also explain why you're having so many metal splinters as well.

    Unfortunately any rim will take a beating in the weather we're having at the moment because of all the muck on the roads- it's quite depressing when you can litter ally feel them being ground away- that's why I'm only using R501's at the mo!
  • peatpeat Posts: 1,243
    The wheels have had at least 5000 miles on them i'd say. That includes last winter.

    I have another front wheel (that came with the bike) which i slung on on saturday, but the grinding came back after a few miles.

    Thet are/were stock Shimano pads, would replacing with a specific wet/winter pad (kool stop salmon etc) be a route worth exploring?

    They are Bontrager Race Lite's. Really nice set of wheels so I don't want to wreck them. I'm starting to understand this 'winter wheels' business now.
  • 6wheels6wheels Posts: 411
    Bar Shaker wrote:
    It is most likely bits of sand and silt in the pads.

    I lightly sand mine clean every few rides.

    Toeing them in slightly so the rear edge of the pad touches first will help keep the main contact area clean.

    I've always adjusted mine so the leading edge touches first!
  • Bar ShakerBar Shaker Posts: 2,313
    If you mean the edge facing the front of the bike, this will trap grit under the contact patch of the pad. It is the normal way to do it, but is fatal for your braking surface in winter.

    Doing them the opposite way means the side of the pads will kick much of the abrasive silt off the rims, so each braking action will clean the rims. The braking performance seems almost the same.
    Boardman Elite SLR 9.2S
    Boardman FS Pro
  • diydiy Posts: 6,680
    If someone could invent some sort of glue on brake surface, they'd make a fortune refurbing all the Dura Ace rims that are worn thin.
  • @ Peat - Once rims start to wear they just catch the brake pad more & then it's the noise of death & destruction a la sandpaper in the wet.

    All you can do is clean your wheels after a ride, maybe look for softer brake pads.

    @diy - they sort of did invent glue for rims, it was the ceramic [open pro's] braking surface rims. They have lovers & haters. I'm banned from talking about them by my mates cos I gleefully remind them how many years old mine are! No winter grinding whatever the conditions & braking is really predictable.Ceramic specific brake pads last a year or more [have a summer bike as well now], & just had to put in the second replacement bearing set into the Hope's they're laced on. :(

    The extra cost put people off & they don't make them any more.
  • 6wheels6wheels Posts: 411
    @Bar Shaker

    Nice bit of logic in that, next time I adjust them I'll give that a try.

    Glad I've got a diskie though (CX Team), even if it weighs a ton.
  • diy wrote:
    If someone could invent some sort of glue on brake surface, they'd make a fortune refurbing all the Dura Ace rims that are worn thin.


    I'm genuinely surprised Farsports or the like haven't yet come out with rims and spokes to match popular factory wheelsets in general. It seems like the most open of open goals to me.
  • DKayDKay Posts: 1,652
    Bar Shaker wrote:
    If you mean the edge facing the front of the bike, this will trap grit under the contact patch of the pad. It is the normal way to do it, but is fatal for your braking surface in winter.

    Doing them the opposite way means the side of the pads will kick much of the abrasive silt off the rims, so each braking action will clean the rims. The braking performance seems almost the same.

    Kool Stop pads have a concave profile for this very purpose. They are shaped so that the rear edge of the pad hits the rim first.

    koolstop-durasa_lg.jpg?w=430&h=430&a=7
  • on-yer-bikeon-yer-bike Posts: 2,974
    The grit that is sprayed on the roads may have been changed. In Kent it is 100% rock salt according to the council website. The noise when i brake is heartbraking and Im using handbuilts. I would only expect my rims to last this winter. The front did last winter the rear was new in Autumn. I think mudguards make matters worse because they direct the muck straight onto the the pads. And no I dont use the rear more than the front when I brake.
    Pegoretti
    Colnago
    Cervelo
    Campagnolo
  • on-yer-bikeon-yer-bike Posts: 2,974
    Oh and chains wear out quickly too.
    Pegoretti
    Colnago
    Cervelo
    Campagnolo
  • DKayDKay Posts: 1,652
    Using handbuilts in winter is a plus, as then you can just replace the rim and not have to junk the whole wheel, assuming your hubs are ok.
  • pilot_petepilot_pete Posts: 1,979
    I gave up after a few winters and bought a CX bike with disk brakes. Superb. It is on its third winter now and the wheels are as they left the factory! I changed the front disk pads last winter, but realised after removing the old ones that they actually had plenty of wear left in them. Chain has been changed a few times, front big ring last winter along with cassette and bottom bracket....which seems to be the weak point as it is starting to rumble again this winter...

    PP
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