Cartridge bearing is rough when pressed in, but fine when taken out

[Manc33]

No idea what to do with this, I have had it in and out several times and sometimes it's smoother than others, but never as smooth as the other cup, which is all running normally.

About to start filing a sliver off the outer bearing ring...

I wouldn't want to use it as it is because it's going to slip on my HT2 spindle and start wearing a line in that.

I reckon the cup itself has taken damage at some point, maybe the chain came off and squeezed it somehow. When taken out, the bearing is as smooth as can be.

[Brucey]

any time you have a press-fit of any kind, onto a bearing, the internal clearance of the bearing will be changed. There does not need to be 'damage' in the cup for this to happen.

cheers

[Manc33]

I can squeeze the bearing in my hand and cause it to have slightly more friction.

Since it's ceramic balls and a metal race, I might just run it as is and see if it loosens up with use.

After very light filing (of the bearing outer and the cup) it seems to have less friction but it's still too much.

As far as I know, this problem doesn't exist with cup and cone bearings! How much friction those have is totally under your control where you're not squeezing a metal ring in like on these cartridge types. I wouldn't mind but the bearings are Hope ceramic, not some cheap brand.

This guy elsewhere:

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warm the cup in boiling water for a while and cool the bearing in a freezer. Drop the bearing straight into the swingarm without a press. sorted.

Another guy said after about 10 pressings and removals he got it smooth. That would depend on how the bearing is rotated IMO. I might try putting a little black dot on the outer ring and trying it at 180° then at 90° to that etc. By sheer fluke it might match up with the cup and be smooth. This BB is miles better than the Deore one I have got in and I really want to use it.

[alexnharvey]

You're not making it sound miles better

[Manc33]

These things have become throwaway items (like the Deore Hollowtech BB) but back in the day the same square taper BB lasted for 3 or 4 bike frames.

[nigelnightmare]

These things have become throwaway items (like the Deore Hollowtech BB) but back in the day the same square taper BB lasted for 3 or 4 bike frames.

And they didn't damage the frame when fitting or removing (as long as it hadn't corroded in).

I can see them making a comeback in professional circles because they're easier to work on even though they are heavier.
They are having to make the bikes heavier to keep within UCI limits anyway So why not have something that is easier to work on and is more durable.

[nigelnightmare]

These things have become throwaway items (like the Deore Hollowtech BB) but back in the day the same square taper BB lasted for 3 or 4 bike frames.

And they didn't damage the frame when fitting or removing (as long as it hadn't corroded in).

I can see them making a comeback in professional circles because they're easier to work on even though they are heavier.
They are having to make the bikes heavier to keep within UCI limits anyway So why not have something that is easier to work on and is more durable.

[Brucey]

some folk will argue (with some justification for sprinters and track riders etc) that ST bottom brackets are more flexy than is ideal. And a ST interface is all you can use (near enough) and still retain a loose-ball bearing design that fits inside a BSC BB shell. Once you make the BB spindle ~24mm (for stiffness) you pretty much have to use cartridge bearings.

So for applications that don't require (or benefit from) very high stiffness, a ST BB is just fine. BITD light steel frames were also quite flexy but these days you can have a lightweight carbon frame which is incredibly stiff in the BB region, which kind of exposes the lack of stiffness in other parts.

FWIW there is a school of thought that some flex during steady state efforts is at least not a bad thing, and may even be a good thing. And 'some flex' clearly doesn't stop you from going quite quickly; after all Sean Kelly wouldn't have won the sprints he did riding his Vitus BITD, even though he always looked to be in danger of tying the thing into an actual knot.

But whilst we are on a more stiffness/less weight = 'good' (and worth compromising other things for) then you shouldn't expect to get anything other than parts that are imperfect in some ways that you personally wouldn't choose them to be.

cheers