When does a BB need replacing?

professorlandslide · Post by **professorlandslide** » 9 Feb 2008, 7:45pm

My bottom bracket's a bit waggly... Only a bit, but if you get hold of the crank arm and pull it, there's a tiny amount of movement. No horrendous crunching yet, but as i expect to be back bike commuting soon due to car clutch issues, is it a good idea to get it replaced now or has it got lots of life left in it?

Ta...

thirdcrank · Post by **thirdcrank** » 9 Feb 2008, 8:34pm

Depends if it is the traditional type, which can be adjusted or a cartridge type, which normally cannot.

I would say if the play in the former type concerns you, have a go at adjusting it. With a cartridge, you can really just bash on until it becomes too much of a nuisance, then replace.

As usual, there is info on Sheldon Brown:

sheldon brown - bottom brackets

meic · Post by **meic** » 10 Feb 2008, 11:37pm

I found that the plastic FAG type cartridge bottom brackets could be moved like that from brand new as they have spring washers inside the plastic casing and are not gripped tight by the end cups.

Out of interest has anyone ever snapped or broken a bottom bracket axle?
I read someone suggest that you should avoid the hollow axles as they are not as strong. Personally, I doubt you could break one.

PW · Post by PW » 11 Feb 2008, 1:03pm

I've never snapped one. I'm a big lad & ride in the Peak hills most of the time, with the odd long distance camping trip in summer. If I don't break them I doubt if anyone else will.

Steve · Post by **Steve** » 11 Feb 2008, 7:35pm

I snapped a BB axle once. On a hire bike riding off the ferry onto a Scottish island, just on a day trip fortunately. It was a solid axle.

professorlandslide · Post by **professorlandslide** » 11 Feb 2008, 8:06pm

Thanks for the replies! Its a cartridge btw... The old ones were easier, certainly...

PD-M320 · Post by **PD-M320** » 11 Feb 2008, 10:46pm

Steve wrote:I snapped a BB axle once. On a hire bike riding off the ferry onto a Scottish island, just on a day trip fortunately. It was a solid axle.

I've managed this too - less glamorously in Neasden on the way from Acton to East Finchley. I was left in the comical situation of having a crank arm hanging off my foot.

It was square taper type... made from some sort of cheese alloy.