Bottom bracket experts

[kaiser]

Hi Kaiser, was that one the UN-91's going cheap on ebay? Was thinking the same thing. Surely if you had some english cups for said BB it would be possible to swap, don't think you can just the swap the italian cups from left to right/right to left though.

Does that make sense :roll:

Yes , yup reckon would need some english cups of the appropriate shell size too.

 

[barry2017]

Are you talking about using an Italian BB in an English shell by swapping the lockring? Italian is 70mm, English is 68, so I suspect it won't work. But I'd be interested if you can.

 

[kaiser]

Are you talking about using an Italian BB in an English shell by swapping the lockring? Italian is 70mm, English is 68, so I suspect it won't work. But I'd be interested if you can.

I think IIRC that you can press of both ends and fit new cups, the idea being that shimano make bearing units with different axle lengths and the cups fitted dictate english/italian or 68/73 size

 

[dbmtb]

I've done this a couple of times with no problems.

A UN71 that needed to run in a 73mm shell instead of 68mm, and a UN91 Dura-Ace BB that went from an Italian threaded to a BSA threaded frame.

As long as you find the right cups, it shouldn't be a problem.

I have a few spare cups lying around in the office and I can see if I have the right ones.

 

[Xesh]

I've done this a couple of times with no problems.

A UN71 that needed to run in a 73mm shell instead of 68mm, and a UN91 Dura-Ace BB that went from an Italian threaded to a BSA threaded frame.

As long as you find the right cups, it shouldn't be a problem.

I did this bitd with a UN91 BB. It had Italian thread and I just knocked those cups off and replaced them with BSA cups from a UN71. The body of the BB is the same it's just the cups that are different. Although, since then, Shimano have changed them again. :evil:

 

[one-eyed_jim]

Wot he sed.

All the cartridges are interchangeable - only the cups differ. So if you can get the cups off an Italian UN91, UN70, 7410, etc. you can replace them with BSC cups - and Bob's thy uncle.

Run boiling water over the fixed cup, taking care not to get any in the bearings. That expands the aluminium cup and softens the Loctite in the interface. Support the flange in the jaws of a vice, and give the axle end a sharp tap with a rubber mallet. The cup should come right off, Lady Jane.

Shimano cartridges use a 30mm press fit, as do many cartridge bearing bottom brackets. That means you can use WTB, TA, Hope, Phil Wood or Royce cups to mount a Shimano cartridge, once you've got the old cups off.

http://www.retrobike.co.uk/forum/viewto ... light=un91

http://www.retrobike.co.uk/forum/viewto ... light=un91

 

[barry2017]

A project coming up for me will be a 1948 Raleigh Clubman. Gorgeous bike, I've always wanted one of the old 531 Raleighs.
One option, if I can't get original bits, might be to fit a square taper BB and run a cotterless crank.
Watch this space!

 

[dbmtb]

Kaiser - I found a little pile of unused ones. Black alloy from UN71/72

Happy to send a couple FOC if you cover postage.

Would send a couple of extras you can give others who might also need.

 

[rienster]

Hi dbmtb,

You would happen to be able to send a right (drive) side cup to Norway, would you? I've got one that's knackered, along with the Cannondale frame it was mounted on.

 

[dbmtb]

If you pay the postage, sure...