Klunk!

[661-Pete]

The time-honoured bugbear - bike that goes "klunk....klunk....klunk" and you don't know where it's coming from.

This is Mrs P's hybrid, a not-very-superior bike and not worth spending ££££££'s on, she's been complaining of the klunk for some time now and this morning's ride, it was very noticeable.

Sounds once for every turn of the pedals, stops when she freewheels. So it's definitely in the drive train and almost certainly at the B/B end.

Well I grabbed hold of the cranks and there definitely seemed to be play in the B/B. One of those sealed cartridge B/Bs for tapered cranks: not worth stripping down. So after the ride I got a new B/B from H*lfords (as I said it's a cheap bike) and it was quite simple to fit: cranks off; unscrew B/B using tool; screw in new B/B; re-fit cranks; done.

But it still klunks. Well at least, it would have needed a new B/B anyway before long.

Doesn't seem to be any bent teeth on the chainset. Must investigate whether it happens on all three rings.

Pedals now fall under suspicion.

Has anyone had a klunk like this which proved impossible to track down?

 

[Zoiders]

It only looks like a sealed cartridge BB - the cups use the same tool but it will most likely be cup and cone underneath.

Sounds like it has a damaged bearing cage.

 

[youngoldbloke]

Are the pedals tight?

 

[661-Pete]

I should have explained: I replaced the entire bottom bracket unit, bearings and all. So wherever it comes from, it's not in there. And yes the pedals are tight and don't appear to have any play.

And I looked for something obvious, like a crank hitting the stays. But it's not that .

So what I'm left with is: shot up pedal bearings, or a chain ring not quite tight on the crankset.

 

[PpPete]

Do you still get the klunk when turning the pedals with the chain off ?

If not - possibly a stiff link in the chain ?
Or even rear mech not quite indexed right ?

Noises can be deceptive about where they are coming from...