UN55 BBs not so good anymore?

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UpWrong
Posts: 993
Joined: 31 May 2009, 12:16pm
Location: Portsmouth, Hampshire

UN55 BBs not so good anymore?

Postby UpWrong » 16 Sep 2020, 5:18pm

I've had a Shimano UN55 become notchy after maybe 300-400 miles. I thought these were good quality, reliable units. I see mine has "Made in Indonesia" on it. It seems I'm not the only one finding problems, https://www.bicycles.net.au/forums/viewtopic.php?t=92890

So I have bought an FSA BB for around 40% of the price of another UN55. It arrived today and looks and feels good.

pwa
Posts: 12732
Joined: 2 Oct 2011, 8:55pm

Re: UN55 BBs not so good anymore?

Postby pwa » 16 Sep 2020, 7:47pm

Sorry yours is rubbish. My latest one has been going for quite a while now and feels good. It feels better now than when new. But I buy a UN55 once every five years or so, so I wouldn't necessarily know if there were a quality control issue. Lots of Shimano stuff has been coming from places like Indonesia for years now, and there is no particular reason why that ought to result in poorer quality.

mercalia
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Joined: 22 Sep 2013, 10:03pm
Location: london South

Re: UN55 BBs not so good anymore?

Postby mercalia » 16 Sep 2020, 8:06pm

I mentioned this elsewhere some time ago. Mine was too tight so when inserted was not smooth motion. It seems to me maybe have a play with it before you buy to see whats it like? I still have a couple of I think UN52s earlier ones that are as smooth as silk when inserted

alexnharvey
Posts: 1219
Joined: 10 Jan 2014, 8:39am

Re: UN55 BBs not so good anymore?

Postby alexnharvey » 16 Sep 2020, 8:28pm

Can't you return it to the retailer?

thelawnet
Posts: 2430
Joined: 27 Aug 2010, 12:56am

Re: UN55 BBs not so good anymore?

Postby thelawnet » 16 Sep 2020, 8:36pm

pwa wrote:Sorry yours is rubbish. My latest one has been going for quite a while now and feels good. It feels better now than when new. But I buy a UN55 once every five years or so, so I wouldn't necessarily know if there were a quality control issue. Lots of Shimano stuff has been coming from places like Indonesia for years now, and there is no particular reason why that ought to result in poorer quality.


erm, I live in Indonesia, and I would not agree with the concept of 'places like in Indonesia' as a generalised idea.

A lot of stuff made in Indonesia is really bad. 'Made in Malaysia' is definitely preferable by a large margin.

And there are lots of quality issues both with finished goods and raw materials (I've bought lots of steel rebar and it's very poor quality and doesn't meet the standard labelled.)

Shimano make parts they regard as low-value and/or low-grade in Indonesia. That's things like Tourney derailleurs, for example.

I don't have specific info on any of these parts, but I would not be surprised if the quality is worse.

pwa
Posts: 12732
Joined: 2 Oct 2011, 8:55pm

Re: UN55 BBs not so good anymore?

Postby pwa » 16 Sep 2020, 8:47pm

thelawnet wrote:
pwa wrote:Sorry yours is rubbish. My latest one has been going for quite a while now and feels good. It feels better now than when new. But I buy a UN55 once every five years or so, so I wouldn't necessarily know if there were a quality control issue. Lots of Shimano stuff has been coming from places like Indonesia for years now, and there is no particular reason why that ought to result in poorer quality.


erm, I live in Indonesia, and I would not agree with the concept of 'places like in Indonesia' as a generalised idea.

A lot of stuff made in Indonesia is really bad. 'Made in Malaysia' is definitely preferable by a large margin.

And there are lots of quality issues both with finished goods and raw materials (I've bought lots of steel rebar and it's very poor quality and doesn't meet the standard labelled.)

Shimano make parts they regard as low-value and/or low-grade in Indonesia. That's things like Tourney derailleurs, for example.

I don't have specific info on any of these parts, but I would not be surprised if the quality is worse.

Interesting. And yes you are correct, I should have been clearer about what I meant by "places like Indonesia", especially as Indonesia is an enormous and diverse nation. I meant parts of the Far East outside Japan with production costs lower than those in Japan. I hope that makes more sense.

I'd be a bit disappointed if Shimano have taken their eye off the ball with this venerable and respected component.

UpWrong
Posts: 993
Joined: 31 May 2009, 12:16pm
Location: Portsmouth, Hampshire

Re: UN55 BBs not so good anymore?

Postby UpWrong » 16 Sep 2020, 8:49pm

alexnharvey wrote:Can't you return it to the retailer?


It's two or three years since I bought it. I have a vague recollection it wasn't that smooth when I installed it, but probably thought it would free up with use.

Brucey
Posts: 40574
Joined: 4 Jan 2012, 6:25pm

Re: UN55 BBs not so good anymore?

Postby Brucey » 16 Sep 2020, 8:54pm

UpWrong wrote:
alexnharvey wrote:Can't you return it to the retailer?


It's two or three years since I bought it. I have a vague recollection it wasn't that smooth when I installed it, but probably thought it would free up with use.


FWIW if the BB threads are not great and/or you install the unit with either (esp the left) cup too tight, you can exert a mighty preload on the bearings. Put it this way, I have reinstalled slightly worn units and the free play in them has mysteriously disappeared once the cups are 'nice and tight'. I think it is easy enough to put the kiss of death on such a unit with poor installation technique. I likewise think that you can prolong the life of such a unit by careful installation with extra (better) grease inside it.

Having said that one model of Shimano ST bottom bracket came with a LH cup that was completely the wrong size for a while, so they can/do screw up.

BTW the OP's link appears to be all about someone who bought a UN26 BB; not the same thing at all.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

rogerzilla
Posts: 1431
Joined: 9 Jun 2008, 8:06pm

Re: UN55 BBs not so good anymore?

Postby rogerzilla » 16 Sep 2020, 9:08pm

I had a bad UN52 (now that's going back) which seized after 70 miles but I've had no problems with UN5x since then. I wish they still made a slightly lighter one with a hollow spindle, like the old UN91.

I think you just got a bad unit.

slowster
Posts: 1608
Joined: 7 Jul 2017, 10:37am

Re: UN55 BBs not so good anymore?

Postby slowster » 16 Sep 2020, 11:25pm

The OP is academic given that Shimano has discontinued the UN55 and UN26 bottom brackets. Their replacements, UN300 and UN100 respectively, are significantly cheaper, which I suspect means a reduction in quality/performance.

So the question is not whether UN55 BBs are not so good anymore, but what Shimano or other brand square taper cartridge bottom bracket is now the best value.

greyingbeard
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Joined: 24 Mar 2015, 10:41pm

Re: UN55 BBs not so good anymore?

Postby greyingbeard » 17 Sep 2020, 6:49am

Can we still buy the old fashioned sort that is separate parts, grease the balls occasionally and last for ever ?
Probably not ???

rogerzilla
Posts: 1431
Joined: 9 Jun 2008, 8:06pm

Re: UN55 BBs not so good anymore?

Postby rogerzilla » 17 Sep 2020, 6:57am

Good cup and cone BBs are available NOS. New ones tend to be the lowest grade of BSO rubbish.

The troubles with cup and cone BBs are that you need three huge, now rare, tools to fit them properly and they are prone to water ingress, which ruins them.

When the remaining supply of UN55 runs out, try Tange-Seiki instead.

Brucey
Posts: 40574
Joined: 4 Jan 2012, 6:25pm

Re: UN55 BBs not so good anymore?

Postby Brucey » 17 Sep 2020, 7:26am

BB-UN300

Image

BB-UN100, with plastic cups

Image

the construction of both the above appears similar in principle to that of Cheng Shin, SunRace, RPM, Tifosi, Token bottom brackets etc. IME it is very easy to overly preload the bearings in this pattern of BB if the centre sleeve between the bearings is not strong enough (and it usually isn't). To avoid excess preload, threadlock is more often required.

In the BB-UN55 etc the inner bearing surfaces are part of the axle, which in theory allows a larger/stronger axle and bearing. In practice they threw some of this potential advantage away by using a relatively small outer diameter for the cartridge unit.

In the new designs there are two seals ( probably neither that good in fact, eg since the outer seal has no lubricant reservoir to keep the seal lips wetted ) to the outside world but should water be lurking inside the frame itself then it will only have to get past a single lip seal on the bearing edge. Such lip seals can be made in various different ways but most are relatively fragile vs the seals on older BB-UN** models.

IIRC the cartridge bearings inside this style of unit are usually populated with 3/16" ball bearings. This is at least a step up from those found in shimano's external bottom bracket designs. I guess the service life will (as usual) be dominated by how the thing is fitted, and the quality of the sealing and lubrication.

IME BBs of the 'new' style are even more vulnerable to being badly installed than most of the older BB-UN** types, since it is possible to install one of the newer ones in a frame even if the threads are so badly cocked an older one can't be installed at all.

As slowster comments above it remains to be seen whether the shimano units are best value for money or not. IME if you want a BB of this style to last, it is a good idea to dismantle it, remove the inner seals from each cartridge bearing, and pack the internal space between the bearings with grease. It remains to be seen if this approach will work with the shimano versions.

I guess the shimano ones will come with a two-year warranty....?

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

JakobW
Posts: 392
Joined: 9 Jun 2014, 1:26pm
Location: The glorious West Midlands

Re: UN55 BBs not so good anymore?

Postby JakobW » 17 Sep 2020, 8:39am

rogerzilla wrote:Good cup and cone BBs are available NOS. New ones tend to be the lowest grade of BSO rubbish.

The troubles with cup and cone BBs are that you need three huge, now rare, tools to fit them properly and they are prone to water ingress, which ruins them.

When the remaining supply of UN55 runs out, try Tange-Seiki instead.


IIRC Tange still make quality cup and cone units; Rivendell ordered a bunch of them a while back in lengths suitable for doubles and triples. I'm sure they're lovely, but they're not a budget option.

PH
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Re: UN55 BBs not so good anymore?

Postby PH » 17 Sep 2020, 8:54am

slowster wrote:So the question is not whether UN55 BBs are not so good anymore, but what Shimano or other brand square taper cartridge bottom bracket is now the best value.

It may be that by the time you've worked that out it's all changed again.
I'm choosing the IRD Defiant, available in the sizes I want and £70 with a ten year warranty. I currently have two and the older is about 2 years, these may be the last BB's I buy. The only issue with them is they look too nice to hide away.
image-31.jpg

https://southerndistributors.co.uk/prod ... 5-defiant/