What will replace the quality of the discontinued Shimano BB-UN55?

[fossyant]

To answer the question it’s already been replaced hasn’t it? There is Shimano’s own Hollowtech and it’s lookalikes plus the result of Cannondale’s pack with the devil, the hated pressfit. Then there’s the Octalink that Shimano have kicked into the long grass.
Are they quality? That depends on your experiences and point of view. Not sure the UN55 was ever quality, just a machined spindle with cups with bearings. It does have a reputation though for going on forever, something the foregoing don’t have.

The UN55 wasn't expensive and just ran and ran until it developed a bit of play, then you changed it. None of this seized bearings or play you get in external/pressfit bearings. You get a warning first, as I've found them to knock first, but still spin freely. I've had GXP bearings seize and I do look after those bearings regularly re-greasing them. My UN91 and UN71 are pushing 30 years old, and other than the rare occasion I take them out to check the frame, coppaslip the threads, they are fit and forget.

 

[Jameshow]

To answer the question it’s already been replaced hasn’t it? There is Shimano’s own Hollowtech and it’s lookalikes plus the result of Cannondale’s pack with the devil, the hated pressfit. Then there’s the Octalink that Shimano have kicked into the long grass.
Are they quality? That depends on your experiences and point of view. Not sure the UN55 was ever quality, just a machined spindle with cups with bearings. It does have a reputation though for going on forever, something the foregoing don’t have.

Pack with the devil!!🤣🤣

In theory the bb30 with decent bearings should outlast a un55 being bigger bearings problem is people put them in with grease and wonder why they creek?

Also manufacturers might not have reamed the BB sleeve to the right tolerance.

Should just tightly push in. If too tight stick new bearing in freezer whilst you take it apart.

Agreed though un55 is a unsung hero!

 

[fossyant]

In "theory" bigger bearings should last, and the wider spacing should be better, but with pressfit and external cups, the bearing seals are very much right in the line of fire from the front wheel.

The square taper BB's have the bearings tucked further into the shell, so engineering tolerances wise, they shouldn't be as good, but the seals aren't in the firing line. That's why they last.

 

[Petrichorwheels]

I'm going back to square taper and internal BB's. I'm sick and tired of forking out for HTII BB's every six months or so.

Interesting.
Some folks claim they are just as good. Though personally i doubt.
On the basis that the un55 just worked. If it aint broke don't fix/tinker with it.
If changing from external bearings to internal what are you planning to do about the bare frame metal that will presumably be exposed?
Also apologies for extra question, if going back to square taper are you planning to source old stock un55s or take your chances with the new one?

 

[Petrichorwheels]

To answer the question it’s already been replaced hasn’t it? There is Shimano’s own Hollowtech and it’s lookalikes plus the result of Cannondale’s pack with the devil, the hated pressfit. Then there’s the Octalink that Shimano have kicked into the long grass.
Are they quality? That depends on your experiences and point of view. Not sure the UN55 was ever quality, just a machined spindle with cups with bearings. It does have a reputation though for going on forever, something the foregoing don’t have.

Am puzzled by your reservations about the un55. What's wrong with going on forever? Do the alternatives promise some orgasmic death?

 

[Cycleops]

Am puzzled by your reservations about the un55. What's wrong with going on forever? Do the alternatives promise some orgasmic death?

Puzzled about what reservations? Just said UN55 was never about quality but simplicity and had the ability go on seemingly forever. Nothing wrong with that.

 

[Jameshow]

Puzzled about what reservations? Just said UN55 was never about quality but simplicity and had the ability go on seemingly forever. Nothing wrong with that.

Depends upon what you mean by quality?

A product that runs for 5yr hard use 10yrs light use is a rare thing these days!

Heralds from the days when engineers ruled the accountants and marketing depts.

 

[ianrauk]

Interesting.
Some folks claim they are just as good. Though personally i doubt.
On the basis that the un55 just worked. If it aint broke don't fix/tinker with it.
If changing from external bearings to internal what are you planning to do about the bare frame metal that will presumably be exposed?
Also apologies for extra question, if going back to square taper are you planning to source old stock un55s or take your chances with the new one?

I've bought a First Components BB from Spa along with a new square taper crankset. Beautifully shiny. Bare metal is Ti. It won't be a problem.

 

[T4tomo]

Nice, very nice. Would match the Chris King headset on the bike, which is a top bit of kit.

The Chris King stuff is lovely. Re headsets, does it make much of difference (the better quality)
I get it with a BB axle which is constantly rotating, but by comparison a head set/ steerer barely moves?

 

[ianrauk]

The Chris King stuff is lovely. Re headsets, does it make much of difference (the better quality)
I get it with a BB axle which is constantly rotating, but by comparison a head set/ steerer barely moves?

I don't know if it makes a difference, but, it does look bloody lovely on the bike.

 

[matticus]

The Chris King stuff is lovely. Re headsets, does it make much of difference (the better quality)
I get it with a BB axle which is constantly rotating, but by comparison a head set/ steerer barely moves?

Different requirements.

Like a shower temperature control; they only move a small distance, but if it's not smooth and predictable, you can get a shock!

 

[Fab Foodie]

Different requirements.

Like a shower temperature control; they only move a small distance, but if it's not smooth and predictable, you can get a shock!

Agreed, frame and fork need to work in harmony, for my 95kg hitting potholes or riding rough roads at speed will put an awful lot of energy through very small contact patches. For a bike to ride nicely, reduce vibrations and turn smoothly those contact patches need to be very accurate and hard-wearing Try loosening one a little bit and go for a ride....
I can certainly tell when mine needs adjusting.

 

[Ajax Bay]

Shimano-bb-un300-square-tapered-bottom-bracket @ £16 - good price. 113mm or 122mm spindles.

 

[rogerzilla]

Mate got new touring bike in June last year for £3,500. BB grumbling after less than 1,000 miles. You guessed it - it's a rubbish UN-300.

A UN-55 in the required length is now unobtainable so he'll try Tange.

 

[alicat]

Holy thread resurrection Batman!