UN 300 vs UN XX sealed BB units

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rogerzilla
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Re: UN 300 vs UN XX sealed BB units

Post by rogerzilla »

fastpedaller wrote: 10 Jun 2021, 5:13pm
rogerzilla wrote: 10 Jun 2021, 3:49pm replacing the bearings is possible, which makes them a lot better value as a long term prospect.
Only if it's possible to buy the bearings at less cost than a complete unit :)
It is if you buy basic quality ones, which is probably what was in there. Go up to the best quality, and it's about the same as a new BB. Most BBs use 69032RS, which is somewhat expensive compared to other sizes. Best quality 62032RS (a much bigger size, used in Brompton folding pedals) are a fraction of the cost. I assume this is related to popularity in industrial equipment and economies of scale.
PT1029
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Re: UN 300 vs UN XX sealed BB units

Post by PT1029 »

I got round to dismantling the RHS/drive side of the BB, it is the same construction as the left side.
Dismembered, inner part of LHS bearing still on axle. RH bearing fully stuck in RH cup.jpg
So it looks the same construction as your usual bog standard 2 cartridge units plus a sleeve. Inner part of LH bearing cartridge still on the axle, the RH bearing cartridge is still fully stuck in the RH cup

RHS, the rusty coloured bit in the middle is the inner bearing .jpg
The brown bit in the midle is the inner diameter of the RH bearing unit.
RHS looking through the central sleeve..jpg
Not really visiable in the photo, the ring spacing out the balls in the cartridge looks bulged at one point - probably explains why I had to grip the axle with grips in oder to rotate it round.

As far as I am aware, the bike was just used around town (cheap Viking (modern) racer).
Loads of new decent bikes (Trek, Specialized) come with similarly constructed BB units. While I have seen quite a few develop play (wear) over time, I heve never seen a near new one self destruct like this one. If you want touring longevity, I'd look else where!
My hunch would be FAG/SKF/Stronglight/TA/new old stock UN 5#/7#
rogerzilla
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Re: UN 300 vs UN XX sealed BB units

Post by rogerzilla »

The TA Axix is a bit fragile. I had one for years, and changed the bearings a couple of times. You really need the proper TA lockring tool to fit it (£££, if you can find one), it has no central sleeve so must just be nipped up, no tighter, and it tends to squeak unless you keep the cups greased where the cartridges bear against them. It's very pretty but not as fit-and-forget as a UN55.
PT1029
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Re: UN 300 vs UN XX sealed BB units

Post by PT1029 »

The TA Axix sounds a bit like the old Stronglight 650/651 units (the "sleeve" is concertinered plastic as far as I remember), you screw in/adjust the cups in the same way you would a cup and cone BB. I have a 650/651 (which ever the steel axled one is), it is about 40 years old. I have a vague recollection I might have replaced the bearings after a round the world trip 30 or so years ago - the bearings were fine, but one of the inner races that sat on the axle had a hairline radial crack in it.
In case you are wondering, I have had it out since then, so hopefully not siezed in the frame!
UpWrong
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Re: UN 300 vs UN XX sealed BB units

Post by UpWrong »

rogerzilla wrote: 13 Jun 2021, 12:11pm The TA Axix is a bit fragile. I had one for years, and changed the bearings a couple of times. You really need the proper TA lockring tool to fit it (£££, if you can find one), it has no central sleeve so must just be nipped up, no tighter, and it tends to squeak unless you keep the cups greased where the cartridges bear against them. It's very pretty but not as fit-and-forget as a UN55.
I have 3 titanium TA Axix BBs. I have the lockring tool but not the drift tool for pushing replacement bearings on the spindle. I've changed one bearing using a seat post as a drift. The new bearing rotates smoothly but is not as free moving as ther oginal bearing on the other end of the spindle. I'm hoping it frees up with use. Ive not had any squesking issues.
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531colin
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Re: UN 300 vs UN XX sealed BB units

Post by 531colin »

If the TA Axis and the Stronglight 650/1 have no metal "sleeve" holding the caged bearings the right distance apart, then what the heck is this BB I have?

ImageIMG_5437 by 531colin, on Flickr
Thats the left side (obviously, no chainrings on that crank and its not a tandem crossover!) ......there's no lockring either, so the cup must be screwed in tight to the sleeve....isn't it?

ImageIMG_5441 by 531colin, on Flickr
Thats driveside, screwed in so the flange is tight against the BB shell, and next to it in my hand is the fitting tool.

That BB has been in use for years....on bikes with full mudguards and effective front mudflaps. Its been in that particular frame for about 3 years; I pulled the R. crank off to attend to the chainrings, which are getting worn. I have in the past re-greased the caged bearings, but this has involved knocking the axle out of one bearing to get access to the inner seals to unpick the seal and re-grease the bearings; I stopped doing this because I wasn't convinced that the benefit of fresh grease outweighed the potential damage from drifting the axle out!

I suppose I could take it right out and look for branding on the sleeve, but the bike is back together now!
slowster
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Re: UN 300 vs UN XX sealed BB units

Post by slowster »

531colin wrote: 17 Jun 2021, 9:55pm If the TA Axis and the Stronglight 650/1 have no metal "sleeve" holding the caged bearings the right distance apart, then what the heck is this BB I have?
That looks like Campagnolo spline pattern. Campagnolo bottom brackets are ISO square taper, and I would guess that is a JIS square taper chainset. I suspect therefore that the bottom bracket might not be Campagnolo but Miche, who have both ISO and JIS taper cartridges in their line up, all of which have BB cups with the Campagnolo spline pattern.
rjb
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Re: UN 300 vs UN XX sealed BB units

Post by rjb »

Later versions of the stronglight 650/1 bottom bracket may have had an alloy sleeve to butt the bearings against allowing the left cup to be tightened against it without crushing the bearings. This thread may give you some help. These could have been superseded by stronglight then outsourcing their bottom brackets to other manufacturers.
viewtopic.php?t=73940
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531colin
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Re: UN 300 vs UN XX sealed BB units

Post by 531colin »

rjb wrote: 19 Jun 2021, 8:28am Later versions of the stronglight 650/1 bottom bracket may have had an alloy sleeve to butt the bearings against allowing the left cup to be tightened against it without crushing the bearings. This thread may give you some help. These could have been superseded by stronglight then outsourcing their bottom brackets to other manufacturers.
viewtopic.php?t=73940
Thanks for finding that old thread.
Apparently mine is a "SBBA" Stronglight BB, and it shows that there was a time when I had some idea what I was doing!
The thread is from 2013, and I still have the spacers I bought un-used....so the original bearings are still in there, still working after 7 summers use!
Stronglight JP400 unit bearings are their "budget" offering, there have been various "up-market" offerings over the years (650, SBBA...)
mattsccm
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Re: UN 300 vs UN XX sealed BB units

Post by mattsccm »

So what the devil do we buy?
Bonefishblues
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Re: UN 300 vs UN XX sealed BB units

Post by Bonefishblues »

mattsccm wrote: 20 Jun 2021, 7:08pm So what the devil do we buy?
Funnily enough, that's exactly why I just bobbed on - to see if there was an 'approved' list yet :lol:
MartinC
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Re: UN 300 vs UN XX sealed BB units

Post by MartinC »

I think the deal is now:
- if cheap and cheerful then almost anything you can find
- for something good, expensive and hard to find then SKF
- otherwise Tange.
robc02
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Re: UN 300 vs UN XX sealed BB units

Post by robc02 »

I've had acceptable service (approx six years of hard commuting and general riding) from Token units BUT I did remove the inner seals and part fill the sleeve with semi fluid grease before using. Others have reported very short life but presumably fitted them as they came.

I needed Campag compatibility so there was little other choice.
mattheus
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Re: UN 300 vs UN XX sealed BB units

Post by mattheus »

robc02 wrote: 21 Jun 2021, 4:00pm I've had acceptable service (approx six years of hard commuting and general riding) from Token units BUT I did remove the inner seals and part fill the sleeve with semi fluid grease before using. Others have reported very short life but presumably fitted them as they came.

I needed Campag compatibility so there was little other choice.
Interesting, thanks.

(I used a Token on a Campag bike and it was the shortest lived BB I've owned! But I did buy it cos it was so much cheaper than actual Campag ... )
cycle tramp
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Re: UN 300 vs UN XX sealed BB units

Post by cycle tramp »

The same sort of discussion has been taking place over here too;

http://thorncyclesforum.co.uk/index.php ... 3#msg84943
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