rogerzilla
Legendary Member
I'll start a new one if you think that's any betterHoly thread resurrection Batman!
What will replace the quality of the discontinued Shimano BB-UN55?
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matticus
Guru
The thread still lives on ... simply because the old BBs lasted so long!
[ Meanwhile, on the Borders of Non-Square Taper Land ...
I've met an old Audax friend on events 2 weeks apart this month. On the first one he told me the saga of getting new bearings glued into his Trek Modane (?). It's at least a 2-day job (plus sourcing the unique bearings). 2 weeks later ... he'd had to replace them the night before!
It's a trek-specific standard which they've now "retired". ]
T4tomo
Legendary Member
probably the sort of thing Token do one of their "replace your shoot pressfit BB with one of our very good screw together non creaky BB""s for.
Ming the Merciless
There is no mercy
- Location
- Inside my skull
That’s appalling , only lasting 16km
matticus
Guru
I think in terms of bearing geometry/size/load, Octalink were little different from square taper, so you should get roughly similar life [dependent on QC and bearing quality]. I've only ever had one "Octa-bike", so am not immersed in the culture, sorry ...
presta
Guru
The Octalink was Shimano, but as the Horizon was Dawes bottom of the range tourer the original square taper BB was just a cheap unbranded one, which may have more to do with the difference.
rogerzilla
Legendary Member
Original Octalink had smaller bearings but its main problem was that the cranks (or the left crank only) came loose on their splines and wrecked themselves due to a basic engineering design flaw.
Drago
Legendary Member
- Location
- Suburban Poshshire
MTB V2 Octalink had deeper splines and is less troublesome, albeit not immune to issues if not extremely diligently installed and torqued.
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raleighnut
Legendary Member
- Location
- One of the 'Elite'
I've got square taper BB's from the 80's in a couple of my bikes, take em out every year or so, pack em with fresh grease or change the bearing races (couple of quid) and they're as free running as new....................the steel and case hardening was far better than anything 'modern'
OP
OP
GuyBoden
Guru
- Location
- Warrington
The old Shimano UN55 BB used larger ball bearings compared with most BB's that use 163110-2RS type cartridge bearings.
The larger UN55 bearings was probably why the BB lasted so long.
If you google the Shimano UN300 that replaced the old UN55, it's not looking good for longevity as I suspected.
The larger UN55 bearings was probably why the BB lasted so long.
If you google the Shimano UN300 that replaced the old UN55, it's not looking good for longevity as I suspected.
fossyant
Ride It Like You Stole It!
- Location
- South Manchester
Over a year on mine so far of commuting, probably nearer 18 months.
Ajax Bay
Guru
- Location
- East Devon
Guy - how do you know this? 'Most BBs'?
Research suggests the UN-300 uses 6903RS (ID17mm, OD30mm) which means (ball) bearings even smaller than the 163110.
If correct, why would Shimano increase the diameter of the spindle where the bearings rest, I wonder?
What "larger ball" bearings are in the UN-55? Might that be the 6002-2RS1?
| Bore diameter | 15 mm |
| Outside diameter | 32 mm |
| Width | 9 mm |
For ref: 163110 = https://www.kineticbikebearings.com/163110-2rs.html
OP
OP
GuyBoden
Guru
- Location
- Warrington
OK, I've installed a Shimano UN300 BB in my bike today, lets see how long it lasts. I've put an excessive amount of grease inside and outside of the BB, which I'll do every year, it's not too tight, so not to overload the bearings.
Shimano UN300 BB on offer for £11
https://www.sprocketscycles.com/products/shimano-bb-un300-bottom-bracket-british-thread?currency=GBP
