Sealed bottom bracket noise

Nuuk

I've got a scuffing noise coming from my bottom bracket. Rather than go into long detail, I have written it all down with a picture at:

http://nickw.worldonline.co.uk/etc/bottom-bracket-noise.html

including what the cause is.

I'm looking for answers to the questions at the end of the page. Thanks.

supersonic

Most cartridge bottom brackets I have seen screw into the frame as one unit, then supporting cup screws in the other side. The bearings are already preloaded and sealed. The only thing moving is the axle. Parts B, C and A cannot turn without loosening the whole unit.

Nuuk

Yes, I've seen that sort and wonder why some like mine have that extra moving part.

nicklouse

It does not.

It is just a not fully sealed BB.

Many are like that.

Nuuk

OK, it's not a fully sealed bearing. But I still need to know why I'm getting the noise when I didn't get it with the previous bearing.

nicklouse - what did you mean by "It does not"?

nicklouse

It does not have an extra moving part.

Looks wornout to me.

Ft a new BB.

Nuuk

If you are referring to the bearing in my picture, it does have the 'extra' moving part (B).

The item shown is an old bearing as I didn't want to remove the new one from the bike just to take a photo.

The question is - should part B be able to turn inside part A and cause a noise? I would guess not because the wear would take a toll on the cup (A).

chez_m356

Nuuk wrote:

The question is - should part B be able to turn inside part A and cause a noise? I would guess not because the wear would take a toll on the cup (A).

no it shouldn't be able to turn, the noise ?, bearings wear and fail, you might have one thats broken up in there, even from new, not all bearings are perfect, you may get one with a bur on it that will cause noise, sometimes they settle down, i had one like that, it wore itself in after a while, it is dead now though, after a good 12 months

WeFixAnyBike

The bb you have installed is of poor quality, on better quality items ie shimano UN55 the outer casing of the left side bearing is not on display. it is incased in the bb itself, thus eliminating your problem.

That would be my fix

Nuuk

OK - thanks guys. I'll look at replacing the current bearing with a Shimano type. Can I assume that all the Shimano bearing don't have part B? And what other 'better quality' brands should I look at?

chez_m356 - this was a problem from the first few days of a brand new bearing. As I said, I have had this bearing out on an almost weekly basis and there is no sign of any problem other than signs in the cup (A) where part B has rotated against it.

nicklouse

Nuuk wrote:

OK - thanks guys. I'll look at replacing the current bearing with a Shimano type. Can I assume that all the Shimano bearing don't have part B? And what other 'better quality' brands should I look at?

chez_m356 - this was a problem from the first few days of a brand new bearing. As I said, I have had this bearing out on an almost weekly basis and there is no sign of any problem other than signs in the cup (A) where part B has rotated against it.

Yes they do have part B but it is in the casting. No they are not always better. If B is rotating then it is seized on the axel.

It does not and should not move in use.

Why it may move. Wrong BB.
poor fitting.
Damaged.

Nuuk

Part B is not seized. I can hold the axle firmly and still rotate part B freely (and vise versa). I can do that even on the old example shown in the photo.

But if I hold the body (part C) and turn the axle, part B moves too.

The Rookie

Well it would, there is always some friction in any bearing, spin the shaft and B will spin if nothing tries to stop it.

Simon

Nuuk

But seemingly too much friction to stop B turning inside A.

The Rookie

Indeed, as B isn't meant to turn inside A, the outer race should be stationary, your point being?

Nuuk

My point being that if it is turning due to too much friction, and causing the noise, then it must be a faulty bearing.

And going back to my original post, this may be a cause of noise in the bottom bracket reported by many others (but not previously explained).

The Rookie

You'll feel if bearing B is stiff or not, if it feels free and the non drive side cup is clamping properly then Bs outer race won't turn.

nicklouse

Nuuk wrote:

My point being that if it is turning due to too much friction, and causing the noise, then it must be a faulty bearing.

And going back to my original post, this may be a cause of noise in the bottom bracket reported by many others (but not previously explained).

very unlikely that B moves. the noise will just be dead bearings.


Again.


Or you are incorrectly fitting it.

Nuuk

If B isn't moving what is causing the scoring on the inside of A?

Dead bearings inside a brand new item? Not impossible of course but fairly unlikely.

And it is correctly fitted.