Bottom bracket square taper cartridges

[RufusChucklebutty]

Anyone know of any difference in qualify between these brands that are all £10 -15 range or would Shimano at £20 be worth the extra for a once a week 6 mile commute bike ?

VP
Halfords
Sunrace
FSA
ETC

 

[I like Skol]

The once a week/6 mile commute thing is possibly the worst type of usage? You use it and maybe get it wet then put it away to fester for a week, rinse and repeat.

The Shimano square taper offerings were near legendary for life expectancy back in the day when Sq taper was the normal style. A UN54/55 would almost be a fit and forget item unless you had a bike a very long time or were doing mega mileages. Not sure about the current offerings as my UN55 is still going strong, but if it were my money I would stump up the cost of an extra pint in a pub and get the shimano one.

Not so keen on the hollowtech BBs , but that's another story......

 

[Ajax Bay]

For that level of use, £10 at Halfords will do the job entirely satisfactorily for at least 5 years (3000 miles).
https://www.halfords.com/cycling/bi...bles/halfords-bottom-bracket-68mm-475638.html
Otherwise the UN-300. Or Spa Cycles.

 

[Chislenko]

I have a cheap and cheerful Halfords number in my winter bike and no complaints from me.

 

[FrankCrank]

For the really budget conscious, bearings can be replaced easy enough:

View: https://www.youtube.com/watch?v=meErJdr_fUI&t=346s

 

[Sharky]

If you have the time to dismantle before you buy, you can determine the current make and length. I would get exactly the same if still available. Other makes might not have the same lengths and might introduce minor issues with the front changer.

 

[RufusChucklebutty]

For the really budget conscious, bearings can be replaced easy enough:

View: https://www.youtube.com/watch?v=meErJdr_fUI&t=346s

I'm an engineer well familiar with changing bearings and I looked into this, its a 16 31 10 bearing which is an uncommon size ( the original manufacturer designed it that way to force you to use their branded parts) and you wont find them from any quality branded manufacturer less than the cost of a new cartridge, you can get them off Ebay but they are going to be unknown quality. Maybe its the same bearing you get on the cheap BB cartridge but you only save a fiver by doing it yourself.

 

[FrankCrank]

I wouldn't say they are 'an uncommon size'. I plan on doing such a bearing upgrade on a cartridge I have that runs real rough. I'll be doing it when next back in Thailand. These are the bearings I'm planning to order for the job

https://www.aliexpress.com/item/100...nYiWYhTo&utparam-url=scene:search|query_from:

I've no idea of the quality of this brand, but it's a budget BB cartridge, so worth a punt I think.

 

[RufusChucklebutty]

I wouldn't say they are 'an uncommon size'. I plan on doing such a bearing upgrade on a cartridge I have that runs real rough. I'll be doing it when next back in Thailand. These are the bearings I'm planning to order for the job

https://www.aliexpress.com/item/1005005204114214.html?spm=a2g0o.productlist.main.45.3505RkMnRkMnJC&algo_pvid=275bf099-ae32-4d3d-a165-55a738b9f90c&algo_exp_id=275bf099-ae32-4d3d-a165-55a738b9f90c-22&pdp_npi=4@dis!GBP!1.76!1.20!!!2.16!1.47!@2101f04d17075507436907388e18c0!12000032142603625!sea!TH!124925076!&curPageLogUid=fiKanYiWYhTo&utparam-url=scene:search|query_from:

I've no idea of the quality of this brand, but it's a budget BB cartridge, so worth a punt I think.

Like I said unbranded , all the ones on ebay posting from China and i dont see any UK online bearing supplier that has them for less than £5 each, most dont stock that size.

 

[Ajax Bay]

If you have the time to dismantle before you buy, you can determine the current make and length. I would get exactly the same if still available. Other makes might not have the same lengths and might introduce minor issues with the front changer.

Before the OP buys, they must know the spindle length (assume BSA threaded and 68mm BB shell width) and procure that length.
Either extract it and the BB may show it or measure as best you can in situ with the cranks off.
Ignore the 'make' and do not try to "get exactly the same make". Many makes have many lengths of spindles. The profile of the square tapered ends are assuredly either JIS or ISO: both standards are well adhered to. Yours will likely be JIS and if you get a BB with spindle the same length no "minor issues with the" FD will be introduced.
if you want to know more then AASSIA: https://sheldonbrown.com/bbtaper.html

 

[faster]

For the really budget conscious, bearings can be replaced easy enough:

View: https://www.youtube.com/watch?v=meErJdr_fUI&t=346s

Be aware though that most Shimano cartridges aren't built like this and cannot realistically be rebuilt. The inner race is the spindle and the outer race is the main body of the cartridge. They do not contain separate cartridge bearings.

This may not be true of the newer UN300 cartridges. It looks like they might be rebuildable.

Even so, as someone said above, it's probably more cost effective to just buy a new cartridge.

 

[Ajax Bay]

. . . . most Shimano cartridges aren't built like this and cannot realistically be rebuilt. The inner race is the spindle and the outer race is the main body of the cartridge. They do not contain separate cartridge bearings.

Have you got a cross-section to share which shows this? I can't envisage the design you describe.

 

[faster]

Have you got a cross-section to share which shows this? I can't envisage the design you describe.

I've not, no. Which part is difficult to envisage?

 

[Ajax Bay]

Which part is difficult to envisage?

"The inner race is the spindle and the outer race is the main body of the cartridge."
Are you suggesting that the spindle has two races integral to it and the main body has two outer races built in?
Are these bearings purely radial or have they an axial element? If the latter, how do you get the compression 'right'?

 

[Jameshow]

"The inner race is the spindle and the outer race is the main body of the cartridge."
Are you suggesting that the spindle has two races integral to it and the main body has two outer races built in?
Are these bearings purely radial or have they an axial element? If the latter, how do you get the compression 'right'?

Afaik un51/55 are sealed bearings which mount on the shaft and the outer one in the threaded insert which is fixed at ds and floating on nds...