speedy25

I need a 68x122.5 bottom bracket for a bike.

I searched for my usual UN55 only to find out they were ALL discontinued. Looking for any others they were ALL discontinued!!
What the hell happened while I wasnt looking? There were BB's in octalink, but no squares.
SO where do I find this product now. Are the other sizes I have now worth a huge sum of money?

thook

70sSanO

There are other Shimano UN BB’s (100 & 300) in that size. Probably lower quality, Tourney, but it is all they support right now.

Or you can find a different brand.

“Quality” square taper BB’s are getting tougher to find. My back-up used to he Origin 8, but they are gone too.

John

2_i 

https://www.xxcycle.com/shimano-bb-u...m-d-nl,,en.php

dsbrantjr

It would appear that they have replaced them with the BB-UN300: https://bike.shimano.com/en-EU/produ.../BB-UN300.html There is also apparently a BB-UN100: https://bicycles.stackexchange.com/q...ottom-brackets

thook

so then square taper cranks are being relegated to the bottom of the barrel parts, too? i've never bought a new crankset, but this doesn't bode well as all i have are square

shelbyfv

You can still pay a lot for a square taper bb if you want. https://www.renehersecycles.com/prod...ttom-brackets/

thook

@shelbyfv never have....never will

Crankycrank

A little pricier than Shimano but not that much and very good quality. Velo Orange English Threaded Square Taper Bottom Bracket (velo-orange.com)

veganbikes

SKF, IRD and Phil Wood all make really high quality square taper BBs. Shimano does the 300 series now which is technically tourney level but higher quality then their old UN-25 at least in terms of the cups (no plastic cups on this one, no comment on bearings). Also Tange-Sekei makes some nice stuff and probably makes at least some of the IRD stuff. Most square taper stuff is going to be sold out due to the pandemic.

thook you should get an SKF and then you won't need to buy a new bottom bracket for a loooooooooooooooooooooong time if ever. Those things last and last and last.

Russ Roth

I've got a couple of the UN 300 series, now a pair of cartridge bearings with a sleeve in the middle instead of a true self contained cartridge. From my feel of them they're probably as good as if not a step up from the UN55. Haven't tried to see how tightly the one cup is fixed to the bearing but if it can be popped off then it may be possible to make a very nice upgrade of the cartridges when the bearings fail if you want something better. Or just spend the money on Phil and have something better.

thook

you know, i'd considered maybe shimano up'ed the quality on the tourney's. i did notice alloy vs plastic cups.

i believe what you're saying, but i'm never gonna spend that much money on a bottom bracket. i'll take up pilates first..lol.

veganbikes

I mean they upped the cup quality at least on the 300 can't speak on the bearings but the cup quality is at least better than the un-26.

Wait what, pilates? I don't quite get it. I know what pilates is but why that as opposed to a really high quality part that will last a long time on something you have already? I wouldn't spend money on pilates when I could just have a nice bike, come on!

2_i 

Traditionally Phil Wood BBs lacked any sealing, other than in the cartridge bearings themselves, apparently being meant for Sunday fair-weather riders. I see that now that now they came up with 'mudguards' that can be only had for an extra fee and anyway are not in stock. If I go expensive, I go for TA Axix with replaceable, like Phil, cartridge bearings. The balls are smaller than in Shimano or SKF, so nominally the bearings may need to replaced more often, but I can have the BB forever and can even swap axles or cups with other brands, yielding a lot of flexibility.

veganbikes

They have had the mudgaurds for a while but yeah maybe not my favorite BB. Though still of good quality with replaceable bearings and axles. I know some folks with some old Phil BBs with no issues and aren't just fair weather Sunday riders.

thook

re: 300's....i guess i misunderstood, then

re: pilates....it was sarcasm, dude. it's not something i have any interest in whatsoever. kinda like spending $170 on a bottom bracket. i appreciate your suggesting it, though

IPassGas

I realize these are sealed bearing BBs, but does anyone add perhaps a fat o-ring and/or plastic washer on the axle to further reduce grime entry into the bearings? The IRC BBs appears to be available and a good price compromise to PW. At least available a few months back when I learned UN55 was archived.

2_i 

TA Axix has quite good sealing and replacement seals can be bought if they fade out. A radical backup solution is to go with ceramic bearings that become more tolerable cost-wise if bought from non-cycling suppliers. Cheap Chinese Ti BBs on Ebay come with O-ring sealings, but I am not sure I would quite trust them. I think I scavenged them for spindles that fit TA Axix and World Class.

JohnDThompson 

Tange still offers a range of square-taper cartridges:

Bottom Bracket | TANGE SEIKI

blakcloud

For another pricey option there is White Industries in 121. Less than the SKF but more than the Shimano or Tange.

Iride01 

Square tapers should have gone out the door the previous century IMO.

Probably the UN-55 left us because it's design got too costly to make compared to other models. There is another model from Shimano that will work. You might have to give up that .5 mm and go with either a 122 or 123mm.

If it were me, I'd put a hollowtech II BB and crankset on it. Or an Octalink BB and crankset if mountain bike.

But still there are plenty of square taper bb's that will work that are still being manufactured. This is much like a particular color of bar tape that is discontinued. You just get another.

Papa Tom

I have a 73 X 122.5 UN55 in the box. Can you make that work?

veganbikes

Ahh ok sorry I probably should have gone to sleep long before that but I hadn't been on in a while thanks to the COVID shot shutting me down for a few days and a move the day before my second shot.

You get a nice part you don't have to replace that you will use a lot that amount goes away quickly. $8.50 a year over 20 years is less than your low end Shimano 100 unit with those plastic cups.

oldbobcat

The UN300 is the replacement for UN55 and UN26. But Shimano is having a difficult time fulfilling demand.

oldbobcat

73s and 68s use the same cartridge and spindle. The difference is the non-drive-side lock ring. So if you still have the lock ring from your 68, you can use a 73.