Should I replace my BB?

swee'pea99

Legendary Member
Just done the last bit of disassmebling before taking my frame for a powder coating. I've always thought the BB, tho' old, was fine. But with cranks off and removed from the frame, it feels...smooth, but not exactly spinny. Twisted in the fingers, you can definitely feel resistance. It's hard to say 'how much', but it's certainly not turning super-freely. Should it be replaced, or is that normal?
 

hotmetal

Senior Member
Location
Near Windsor
I'm not a bike mechanic, but I would say that if it feels smooth when you turn it with your fingers, cranks detached, it's fine. I find that most BBs don't 'spin' like a wheel hub even when new - mainly cos they're packed with grease. In fact, I would even go as far as to say that when I have replaced ones that were creaking when pedalling hard, they were in fact looser and more 'spinny', but not smooth.

That's my opinion, but I'm sure someone better qualified can either confirm or disagree...
 
OP
swee'pea99

swee'pea99

Legendary Member
Thanks all. It's definitely smooth...not a trace of notchiness about it. Guess it's good for a few more miles.
 

02GF74

Über Member
hotmetal said:
I'm not a bike mechanic, but I would say that if it feels smooth when you turn it with your fingers, cranks detached, it's fine. I find that most BBs don't 'spin' like a wheel hub even when new - mainly cos they're packed with grease. .
agreed plus the seal has a lip that will cause some drag.

ofcourse you cannot expect it to spin like a wheel - think of the moment of intertia of the rim compared to that which a BB has, even if pedals are fitted - you would need to connect something to the BB a bigger diameter than the pedals for the same effect.

Having said that, if you remove chain, the pedals should spin freely but nowhere near as many revs as a wheel.


Grip the BB body and try to move the spindle from side to side - there should be no play, a little bit of play is ok but no sloppiness!
 
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