Bottom brackets

Discussion in 'General Cycling' started by D.M. Procida, Feb 25, 2011.

  1. D.M. Procida

    D.M. Procida Guest

    How long do your bottom brackets usually last?

    I replaced mine two or three thousand kilometres ago, and there's a
    curious grainy feeling in the pedals again. Surely they can be expected
    to last longer than that?

    D.M. Procida, Feb 25, 2011
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  2. D.M. Procida

    Tom Crispin Guest

    On Fri, 25 Feb 2011 23:42:35 +0000,
    Mine has just clocked 10,000 miles - since the computer was replaced.
    I cannot recall how far it had done on the previous computer.
    Tom Crispin, Feb 26, 2011
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  3. I've only ever have one give up, and that was on a bike I bought
    second-hand. Sorry.

    Matthew Vernon, Feb 26, 2011
  4. D.M. Procida

    Alex Potter Guest

    The original BB on my BSO lasted three-quarters of the way round the
    Netherlands. The replacement is still going strong, but I've only put
    about 2000 miles on it.
    Alex Potter, Feb 26, 2011
  5. D.M. Procida

    Tosspot Guest

    Last one was at 8,000 miles daily commuting when the bike went. I think
    a modern sealed one lasts just about forever.

    2-3,000 kilometres sounds like either something else is wrong or name
    and shame on the manufacturer front.
    Tosspot, Feb 26, 2011
  6. "Curious grainy feeling" - that's nice, because, I've been meaning to
    ask about that for a long while. I sometimes have this, and my
    conclusion is that it's a sign of an underlubricated chain. It usually
    goes away on applying lube, and it's much more noticeable in higher gears,
    which I would explain as being the links have to bend more sharply and
    more quickly when on small sprockets.

    Is my analysis plausible - and how's your chain?
    Julian Bradfield, Feb 26, 2011
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    I replaced one once. The bike was 20 years old and had covered probably
    somewhere around 20,000 miles.

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    Just zis Guy, you know?, Feb 26, 2011
  8. D.M. Procida

    Peter Clinch Guest

    The triplet seems pretty heavy on them... It was 2nd hand and I
    don't know quite how many miles it had done, but in the last year
    I've had the LBS replace 2 and the third is starting to be on the
    way out.

    It's a great beast, but pretty heavy on transmission :-(

    Peter Clinch, Feb 26, 2011
  9. D.M. Procida

    Danny Colyer Guest

    That's one hell of a daily commute. How long did you keep it up for?

    Danny Colyer, Feb 26, 2011
  10. D.M. Procida

    Danny Colyer Guest

    I replaced one on a cheap bike once, probably after about 15,000 miles.

    My current BB is on about 10,000 miles. Over the last couple of weeks
    I've been feeling an occasional knocking through my right foot whose
    cause I haven't yet identified. It /could/ be the BB, but I don't think
    it is.

    I replaced my previous BB after about 17,000 miles, but only because I
    bought new cranks that needed a shorter BB axle.
    Danny Colyer, Feb 26, 2011
  11. D.M. Procida

    Paul-xxx Guest

    I'd agree. In many cases it's also probably due to the smaller
    sprockets not being used as much as the bigger ones and thus not being
    as worn as the chain, so not fitting quite as well.
    Paul-xxx, Feb 26, 2011
  12. D.M. Procida

    D.M. Procida Guest

    D.M. Procida, Feb 26, 2011
  13. D.M. Procida

    D.M. Procida Guest

    Well, I'm sure Shimano will be very ashamed when I identify them as the

    D.M. Procida, Feb 26, 2011
  14. D.M. Procida

    Simon Mason Guest

    On my winter bike which is now 6 years old, it is on its 3rd BB and
    the bike will have done roughly 11000 miles.
    The bike I use in summer is still on its original BB but it is part of
    a Campag Record groupset and so I'd expect it to last a fairly long
    Simon Mason, Feb 26, 2011
  15. It's not been a nice winter for chains. I even cleaned mine, which is
    saying something :)
    Is there any play in the BB?

    Matthew Vernon, Feb 26, 2011
  16. D.M. Procida

    A.Lee Guest

    Once a year on a cyclo-cross bike that endures 8 - 12 races in poor
    conditions. So maybe 200 miles?
    It's the weather/road conditions that cause them to fail, even so called
    'sealed' bearings get a coating of fine grit in wet muddy conditions.

    A.Lee, Feb 26, 2011
  17. D.M. Procida

    D.M. Procida Guest

    How?! Can grit travel through metal?

    D.M. Procida, Feb 26, 2011
  18. D.M. Procida

    Tosspot Guest

    Then my bet is the BB is OK and it lies elsewhere. Pedal bearing,
    chain/sprocket interface, or memorably a twig stuck under a mudguard.
    Tosspot, Feb 26, 2011
  19. D.M. Procida

    Tosspot Guest

    I'm pretty quick and always cycle with the sun...
    Tosspot, Feb 26, 2011
  20. What do you mean by fail? Something catastrophic or pedals really tough
    to turn? Or not in the appropriate condition for a good performance for
    racing? Or maybe it is just you - your style and type of riding - some
    people seem to be notoriously bad for going through BBs.

    I would certainly expect a much greater life-time than 200 miles for a
    BB for utility bikes - even when used in crappy conditions and not
    cleaned. I'm pretty sure if I only less than 200 miles out of a component
    I would be back at the LBS complaining about not fit for purpose.
    Andy Leighton, Feb 26, 2011
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