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Brake Blocks Damaging Rims

spencerse78edspencerse78ed Posts: 13
edited May 2007 in Workshop
Took my new wheels (see: http://www.eastonbike.com/PRODUCTS/WHEE ... st_II.html) out for a 35 mile blast this morning. A short while into the ride the when I applied the brakes the brake blocks started to make a horrible grinding noise on the rim. This was worse on the front. Luckily I managed to get home without having to use the brakes much (quiet country roads). When I got home I took the brake blocks off, they seem to have small bits (flakes) of aluminium embedded in them!! I assume that this is what is causing the horrible grinding noise. The brake blocks are Shimano. What's going on? There must surely be some issue with these brake blocks?

Posts

  • Mister PaulMister Paul Posts: 719
    It's normal to get small metal bits embedded in your pads, especially with new rims.

    Just pick them out with a pen knife.

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  • I'm worried that the rims will get damaged though
  • Mister PaulMister Paul Posts: 719
    Was it raining? They seem to make nastier noises when it is.

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  • No rain. I did pick out the flakes and sanded the blocks a little with some sandpaper. I went out this morning for a 50 miler and they seem a lot better. The rear is fine, but the front, although a lot better, still seems to be making a rougher noise than the rear. I haven't checked the blocks again yet. My other rims did not do this when they were new, although they were only bog standard cheapies supplied with the bike. Why do you say this is normal? Is this the rims bedding in? Or is it something to do with the maching or polishing when built? I'm wondering if different brake blocks would make a difference?
  • JWSurreyJWSurrey Posts: 1,173
    My Campag. machined rims were noticably worn down after 500 miles of riding on Tektro brake blocks.
    I ensured I picked out the metal flakes/swarf about once every 2 or 3 weeks.
    Are your rims machined?
    Not had any such problems with my cheaper machined rims on Campag. blocks.

    Have changed my Tektro blocks for Swissstop blocks.

    If it's wet, I'm religious about cleaning down the rims after riding too, to remove that gritty "grinding paste" build-up. (Hose off rim, stand for 5 minutes, wipe round with an old rag).
  • hairytoeshairytoes Posts: 645
    Don't use sandpaper, scrub off with a toothbrush or somesuch.

    Particles from the sandpaper will end up in the blocks, these WILL grind away your rims.

    ++++++++++++++++++++++++++
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  • monty_dogcpmonty_dogcp Posts: 382
    Dress the face of the blocks with a file to remove any embedded debris
  • cougiecougie Posts: 22,512
    The metal is from your rims. If its noisy or wearing a ridge - look at the blocks to pick the metal out with a pin or something.
  • hubgearfreakhubgearfreak Posts: 480
    do what monty tells you to do.
  • rgismergisme Posts: 1,598
    I bought some brakes off ebay that were new and had really crappy blocks in them. I'm convinced they must have been for ceramic rims, although that would be unusual on 700c wheels! Anyway after a short ride in which I could see aluminium shavings flying off the wheel as I braked, I quickly changed them for some Salmon pads which gave no problem at all. So my advice would be, if it happens again after you've removed the debris - change to better quality pads!
  • andrew_sandrew_s Posts: 2,511
    I've had the same problem with Shimano pads. It can wear your rims quite badly. I've had a rim that didn't last as long as the tyre I'd put on it. You can pick the bits of grit and metal out and trim down the pad surface, but it never seemed to help for very long.

    I use Koolstop pads now, and don't have the same problem.
  • venstervenster Posts: 356
    I had a similar problem, and changed the pads to Bontrager ones. Didn't happen again.
  • Yes Shimano brake pads are to be avoided - though I have to say that my only experience is with XT cantis.
    Forum consensus is that Koolstop Salmon is the way to go.
    Dave

    David Jones

    My bikes http://picasaweb.google.com/lb1dej

    My clubs: Buxton CC - South Manchester CTC - VCC - VTTA
  • pbiggspbiggs Posts: 9,232
    Yes, Koolstop salmon pads are less susceptible to picking up bits of grit and metal in the first place.

    <i>~Pete</i>
    <i>~Pete</i>
  • richardjallenrichardjallen Posts: 691
    What are Swissstop like for this?
  • JWSurreyJWSurrey Posts: 1,173
    I've found the Swissstops to be better than the standard Tektros.
    Great in dry, good in the wet. No noise at all, very little marking of the rims.

    I've not had a swarf problem either with them - although after a couple of wet gritty Cotswold rides, I did find a single 0.5mm long metal shaving in them - not had any since, in about 250 miles.

    It's difficult to say if this is due to the rims having bedded in now / drier weather.
    Also, I bought the metal shoes, which I assume results in better heat disappation (I spend a lot of time in the North Downs at the moment).

    They get rave reviews from people who use them, and they're better than what I had before. I suspect the improvement would be even more marked if I wasn't using Tektro calipers, which are noticably more inefficient than my Campags.

    I'm going to try a set of Koolstops on my 105/Mavic Open Pro setup, just for comparison - but this won't be for some time.
  • Bought some Swissstop pads today, œ22 !!! Hope there worth it! I'll be trying them ASAP.
  • JWSurreyJWSurrey Posts: 1,173
    <blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by spencerse78ed</i>

    Bought some Swissstop pads today, œ22 !!! Hope there worth it! I'll be trying them ASAP.
    <hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
    Cool! Enjoy!
    22 is a good price for a pair with shoes.
    Which store? It's worth it, if it saves you having to buy new rims.
  • vernonlevyvernonlevy Posts: 969
    <blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by JWSurrey</i>

    <blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by spencerse78ed</i>

    Bought some Swissstop pads today, œ22 !!! Hope there worth it! I'll be trying them ASAP.
    <hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
    Cool! Enjoy!
    22 is a good price for a pair with shoes.
    Which store? It's worth it, if it saves you having to buy new rims.
    <hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
    Koolstop salmon are a lot cheaper and are very good.
  • The œ22 was just for the blocks! From Mosquito bikes in London
  • JWSurreyJWSurrey Posts: 1,173
    Ah - sbrsports claim to have them with metal shoes for 23.39, but to be honest, I had a set on order with them through the shop for about 4 weeks, since they're just up the road, then they rang up to ask me "what order?".
    A bird in the hand is worth two in the bush.... hence I picked up two pairs off-the-shelf in Condor.

    How are you finding them? I noticed they're more powerful and just as progressive than the Tektro standard blocks.

    http://www.sbrsports.co.uk/461-58040
  • As there not on my commuter bike (there on my weekend road bike) I won't be checking them out till the weekend. I'll post the outcome once tested.
  • I've now fittes and ridden my bike with the swisstops on. There very good, much better than the simano blocks. Much more powerfull and progressive. I'd say well worth the extra cost. Gets what you pay for I guess.
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