Shimano BB-UN71 Bottom Bracket modern equivalent.

[FluffyChicken]

Which size do you need? I'd choose from the IRD range: QB75 or QB95, pricey but for a reason. Or the Tange-Seiki LN 7922, but both brands/modells can be cumbersome to get, I guess.

The IRD BBs I’ve had have been rubbish and did not last well, the Tange are excellent though and I would consider them a modern version of the UN7* - well sealed bearings, alloy cups, hollow axle.

Which is interesting given Tange make the IRDs, it's why they have their bearings.

UN55 is the nearest in Shimano land, much the same now bar the plated axle, hollow iirc now too. Should have the same large bearing in them that cartridge style cannot do.
Some nice cheap TH Industries style etc BB on eBay Amazon with trendy blue cups. good, who knows.

 

[Trebz]

Which size do you need? I'd choose from the IRD range: QB75 or QB95, pricey but for a reason. Or the Tange-Seiki LN 7922, but both brands/modells can be cumbersome to get, I guess.

The IRD BBs I’ve had have been rubbish and did not last well, the Tange are excellent though and I would consider them a modern version of the UN7* - well sealed bearings, alloy cups, hollow axle.

Which is interesting given Tange make the IRDs, it's why they have their bearings.

UN55 is the nearest in Shimano land, much the same now bar the plated axle, hollow iirc now too. Should have the same large bearing in them that cartridge style cannot do.
Some nice cheap TH Industries style etc BB on eBay Amazon with trendy blue cups. good, who knows.

You mean like this:

https://www.ebay.co.uk/itm/Fsa-Th-Indus ... SwVeZdC6G3

And this:

https://www.ebay.co.uk/itm/Tange-Square ... SwZTldy-Lp

As the bike will be my general runabout I'm not really bothered about it having a period correct bottom bracket, I mean, I'll never actually see it will I hehe. I guess my question should have been 'Which modern bottom bracket do you all use when a period correct one isn't suitable or available'. I'm sure there are a good few out there for around a tenner which would give similar performance to the good old UN71 or any of the others in that range from BITD.

 

[Trebz]

Re: Re:

Depending on size, I may have a decent one spare. Also have a ti bb that has replaceable sealed bearings I'm not currently using.

I'll measure up today and let you know if I'm interested in the Ti one. It's for my daily runabout so Ti may be overkill

 

[legrandefromage]

I'm sure that era of Saracen was 73mm shell

maybe

I found the RPM branded ones wore out very quickly especially in the wet.

 

[Trebz]

I'm sure that era of Saracen was 73mm shell

maybe

I found the RPM branded ones wore out very quickly especially in the wet.

Hhhmm noted, thanks Cheese.

 

[FluffyChicken]

Re:

I think Chris's Saracens were all 73mm shell too, measure to check though.

just buy a UN55 for a run about, that's what I'd buy now, that's after buying Ti & Steel lightweight alternatives over the past years on retrobike.
You shouldn't need to worry about it then. it'll just do its job.



p.s. I was meaning these blue cupped bb's that seem to have flooded eBay when I search, with your finest Chenglish descriptions too. https://www.ebay.co.uk/itm/174273365725 no idea what they are like.