not broken one of these Shimano BBs before

[Sweep]

If you want nice reliable UN55s or similar, buy them now while you still can (just); they are being replaced by something else, cheaper and worse looking.

Honest question.
Has it been established that the new ones are worse?
If so, how?
I stress that I don't care how they look.

[Brucey]

If you want nice reliable UN55s or similar, buy them now while you still can (just); they are being replaced by something else, cheaper and worse looking.

Honest question.
Has it been established that the new ones are worse?
If so, how?
I stress that I don't care how they look.

Not beyond all doubt.

But it does seem likely; even the best BBs of this type (Tifosi, Token) can fail quickly, even though they have extra seals like the shimano units have.

cheers

[rogerzilla]

They've been a bit worse since the hollow axle ones were dropped; UN7x and UN9x were better, and UN55 is only the "half decent" survivor.

If Shimano is willing to sell you a square taper crankset these days, it'll be the very lowest grade so they're not going to keep making good BBs so laggards like us can hold onto nice old cranks. We should all buy a new bike every year to help the economy, they think.

[NATURAL ANKLING]

Hi,
I've not brought any new BB's For several years.
I'm now getting a bit worried and see I'm going to have to have a look into this.

[drossall]

Stronglight still make square-taper chainsets, so I don't suppose they'll stop making the BBs any time soon. Try Spa Cycles or SJS.

[NickJP]

I think that longer crank bolts can help prevent failure of the taper at that point, as the longer bolt means that the bolt thread extends past where the crank pulls onto the tapered axle. Here's a photo of three crank bolts - a Sugino on the left, a Campagnolo on the right, and I don't know the brand of the centre bolt. When in use, the Sugino doesn't extend the full depth of the taper on the crank, the centre bolt extends approximately full depth, and the Campagnolo extends past that point:

[rogerzilla]

Stronglight still make square-taper chainsets, so I don't suppose they'll stop making the BBs any time soon. Try Spa Cycles or SJS.

Aren't they ISO?

[drossall]

Yes sorry, not sure how I overlooked that.

[Brucey]

Yes sorry, not sure how I overlooked that.

Stronglight cranks made in Japan (which is most if not all of them now) such as the 'Impact' are JIS not ISO. So are the stronglight branded bottom brackets such as JP400.

cheers

[NATURAL ANKLING]

Hi,
I mentioned Bolts early on in the thread.
I will have to go and look but I think in actual fact the hole (untapped) Which is always deeper, and the threaded portion of the hole, is quite deep.
It's always a good idea to check threaded depth of hole When you are going to use a non-standard bolt length.
You don't want a situation where the thread of the bolt Bottoms out in the threaded hole, and thus no longer performs the task in securing the parts together effectively.

Edited/
P.S.I have no knowledge of the subject, but as an offshoot of threads, And this may well have no relevance here, internal thread roll taps.
Where internal threads like in holes are rolled not tapped.
https://www.yamawa.eu/wp-content/upload ... 17_web.pdf
"Only suitable for stringy materials "?

[drossall]

Stronglight cranks made in Japan (which is most if not all of them now) such as the 'Impact' are JIS not ISO. So are the stronglight branded bottom brackets such as JP400.

Thanks. As I'm generally using both their cranks and their BBs, it's not something I've worried about so much, barring a general awareness.

[bgnukem]

I think the Stronglight Impact, as well as the Spa Cycles triple chainsets, are mostly based on the Sugino XD2 crank arms and are all JIS taper. I've got several Spa sets with 'XD2' in relief letters on the backs of the cranks.

Bit worried about the shrinking supply of decent square taper brackets!