How long do BBs & chainsets last?

in message <[email hidden]>, AP

(') said:

I just fitted a new BB and chainset (both Campo) and they work so well
and they were so cheap and I have a feeling that cheap today could become
damn-near-unobtainable-and-with-a-price-that-reflects-it in the not too
distant future. I do about 75 miles a week, London commute, in all
weathers, year round. Any ideas roughly what total mileage I might expect
from me new bits?

My winter bike is still on it's original BB. It needs a strip and regrease
now, but that's fourteen years and at least 20,000 miles.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; Men never do evil so completely and cheerfully as when they
;; do it from  religious conviction."          -- Pascal

AP said:

I just fitted a new BB and chainset (both Campo) and they work so
well and they were so cheap and I have a feeling that cheap today
could become damn-near-unobtainable-and-with-a-price-that-reflects-it
in the not too distant future. I do about 75 miles a week, London
commute, in all weathers, year round. Any ideas roughly what total
mileage I might expect from me new bits?

Cranks will last practically forever if fitted properly (ie not too loose)
and you don't crash em.

Chainrings: Tens of thousands of miles if they're used only with nice and
fresh chains (ie hardly elongated). Maybe only a few thousand otherwise.
The outer ring should last longer than the inner anyway.

BB: Could be twenty thousand miles or more with some luck and if the BB is
happy the way it's fitted. They can wear out very prematurely (eg 3000
miles) if some imperfection with frame shell's thread or faces are causing
the bearings to bind. During fitting, you can tell all is not right if the
spindle becomes much more difficult to turn by hand when the cups are fully
torqued. In this case either the frame should be fixed, or the BB fitted
less tightly and with threadlock.
Weather isn't relevant as the BB is well sealed.

If you can still get them very cheaply, and you're happy with the weight of
the things, I'd say it's worth stocking up with two or three spare BBs now.

Spare chainrings will be available for many years to come from various
sources.

~PB

Simon Brooke said:

My winter bike is still on it's original BB. It needs a strip and
regrease now, but that's fourteen years and at least 20,000 miles.

If it's an old style adjustable BB, it's not really relevant to AP's
question.

For cartridge type, greasing isn't possible without prising the seals off,
risking damage in the process.

~PB

Pete Biggs said:

Simon Brooke said:

My winter bike is still on it's original BB. It needs a strip and
regrease now, but that's fourteen years and at least 20,000 miles.

If it's an old style adjustable BB, it's not really relevant to AP's
question.

For cartridge type, greasing isn't possible without prising the seals off,
risking damage in the process.

Likewise, one would not expect a cup'n'cone BB to not bind if the cups
are fully torqued..

...d

Thanks Pete et al - much appreciated. Not an immediate worry then...
"Pete Biggs" <[email hidden]> wrote in
message news:[email hidden]...

Quoted message said:

AP said:

I just fitted a new BB and chainset (both Campo) and they work so
well and they were so cheap and I have a feeling that cheap today
could become damn-near-unobtainable-and-with-a-price-that-reflects-it
in the not too distant future. I do about 75 miles a week, London
commute, in all weathers, year round. Any ideas roughly what total
mileage I might expect from me new bits?

Cranks will last practically forever if fitted properly (ie not too loose)
and you don't crash em.

Chainrings: Tens of thousands of miles if they're used only with nice and
fresh chains (ie hardly elongated). Maybe only a few thousand otherwise.
The outer ring should last longer than the inner anyway.

BB: Could be twenty thousand miles or more with some luck and if the BB
is happy the way it's fitted. They can wear out very prematurely (eg 3000
miles) if some imperfection with frame shell's thread or faces are causing
the bearings to bind. During fitting, you can tell all is not right if
the spindle becomes much more difficult to turn by hand when the cups are
fully torqued. In this case either the frame should be fixed, or the BB
fitted less tightly and with threadlock.
Weather isn't relevant as the BB is well sealed.

If you can still get them very cheaply, and you're happy with the weight
of the things, I'd say it's worth stocking up with two or three spare BBs
now.

Spare chainrings will be available for many years to come from various
sources.

~PB