Any way to keep rim brakes from wearing down rims?

Discussion in 'Cycling Equipment' started by Strelok, Nov 27, 2011.

  1. Strelok

    Strelok New Member

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    I'd really like to know if there is. This is actually the only thing that makes me want disc brakes.
     
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  2. davereo

    davereo Well-Known Member

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    No need to worry about pads wearing out rims. I have a set of Veulta airline wheels with over 50000 miles and and the factory wear line machined into the rim is still there.
     
  3. sitzmark

    sitzmark Member

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    Yes - don't use them. :)

    Clean pads often, especially after riding in wet sandy conditions. Check often for foreign material embedded in pads. Glass shards, metal shavings, sand grains, etc will grind into rim surface and speed wear.
     
  4. alienator

    alienator Well-Known Member

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    I've got about 15,000 miles on my front rim--the front wheel see's most of the braking--and the rim is still in great shape. Yup. Even though I live in the windy, gritty, dusty desert, the front rim is just fine.
     
  5. dabac

    dabac Well-Known Member

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    You can get ceramic coated rims. Pricey, prone to chipping if treated roughly but virtually endless life during riding conditions. Better braking in the wet too.
     
  6. tafi

    tafi Member

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    If brake wear won't get them then eventually fatigue will. It is not possible to have a rim which will last forever. Not even disc rims will last forever. There are too many variables to quanitfy how long a rim will last and in reality it isn't worth worrying about.

    This is also no reason to bother getting disc brakes since the rims will still need replacing at some point. The only reasons to get discs are if you will be riding a lot off road and through a lot of mud and water. In these conditions disc brakes offer better consistency than rim brakes. I have also seen far more failed disc brakes than failed rim brakes.
     
  7. Strelok

    Strelok New Member

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    I just realized that it's getting hard to find non disc mountain hubs. :/
     
  8. dabac

    dabac Well-Known Member

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    Really? where are you looking?

    Besides, there are no issues (apart from aestethics, and maybe a tad of weight) with running disc hubs and rim brake rims.
    Sure, you'll get a tension offset in the front that wasn't there before, but front wheel failures are still rare enough not to make this worth worrying about.
    And unless you're looking at through-axle designs, or one of those beefed-up, AM/DH-specific rear axles, the concept of a "MTB" hub is quite silly.
    And if you're into those, then you should really be using disc brakes anyhow.
    A supposedly "road" hub with a good seal design around the bearings will do just as well for the majority of MTB use.
     
  9. 531Aussie

    531Aussie Well-Known Member

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    Quote: Originally Posted by Strelok . I'd really like to know if there is. This is actually the only thing that makes me want disc brakes.

    Braking in the wet wears rims out much faster. It's not just water that gets on there, but grit/grime/dirt (whatever) also gets on the pads, and with the water (I reckon), acts like wet sandpaper. I reckon I chewed through a front Mavic CXP33 in one winter of very wet commuting. I sometimes put on a crappy old front wheel in I think I'm gunna get stuck in the rain.

    As the other guys said, cleaning your pads and picking out the imbedded "aluminium dust chunks" more often will help.
     
  10. cheetahmk7

    cheetahmk7 Well-Known Member

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    My Ksyrium SLs are fine after around 50,000 km.

    In fact I have only had to replace one brake pad. Given that they come in a box of four, I still have three spare pads.
     
  11. 531Aussie

    531Aussie Well-Known Member

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    ^ That's pretty good. Are the braking surfaces concave?
     
  12. cheetahmk7

    cheetahmk7 Well-Known Member

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    I shall have a look when I get my bike back. (Unfortunately my frame didn't last as long as the pads or rims, having just cracked)
     
  13. alienator

    alienator Well-Known Member

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    I'd check brake centering, too. Wear should be symmetric between brake pads on a given wheel.
     
  14. An old Guy

    An old Guy Member

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    If you lock the wheels, there is no motion between the wheel and brake pad so there is no wear. It is sort of rough on the tires.

    The best way to avoid rim wear is to buy decent rims. I use Mavic OP and they seem to last for a long time the way I use them. In addition to good rims, let air resistance reduce most of your speed - sit up well before you need to brake. Finally brake gently. If you are not going to lock the wheel, there is no reason to slow quickly.

    I have never come close to wearing out the braking surface of rims. Perhaps you have some local condition that is causing your issues.
     
  15. alienator

    alienator Well-Known Member

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    On the road, locking up tires is not the way to slow down fast, anyway. Sliding friction (i.e., tire sliding along the ground) is less than static friction (braking without locking the tire up, meaning there's no motion between the contact patch and the road). Learning to brake properly (for emergency stops or fast downhill corners) means learning that lesson and putting it into practice.
     
  16. An old Guy

    An old Guy Member

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    The question was how to prevent wear of the braking surface.

    ---

    ( I will slur a few terms to keep this simple.) Dynamic (sliding) friction has a single value. Static friction has a range of values from 0 to a maximum. The maximum of static friction is larger than the value of dynamic friction. But in general, the static friction values used by bicyclists - including racers, is less than the dynamic value.

    Proper braking depends on what you want to accomplish. I don't recall ever having my braking approach the deceleration of a locked wheel except as the bicycle comes to a stop. In that case the tire does not skid. I guess you have different needs.
     
  17. alienator

    alienator Well-Known Member

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    Yes, the question was about how to reduce wear. So?

    Maximum braking on a bike occurs at the point when the bike starts to rotate over the front wheel. You'll note that when that happens, the front is not locked. After that point, the braking force cannot be increased because it would just increase the angular velocity of the bike around the front wheel's axle.
     
  18. kdelong

    kdelong Well-Known Member

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    Strickly reducing wear? You could grease them but that would attract dirt and probably act like grinding compound. Therefore you would want to use a good dry lube.
     
  19. alienator

    alienator Well-Known Member

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    Would furniture polish or car wax be ok?
     
  20. An old Guy

    An old Guy Member

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    Try to stay on the subject of the question. I do.

    ---

    As to your comment: The quickest way to stop a bicycle is to do a bunny hop, while in the air lock the brakes and turn the bicycle 90 degrees to the direction of travel, and land leaning away from the direction of travel.

    The only problem is that it takes skill.
     
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