Replacing cup & cone BB with sealed. But which?

[sefton1275gt]

Also, there seems to be countless lock rings on sjs

 

[sefton1275gt]

I just ordered a Tange 3922 from a company called Hubjub. Couldn’t source the n55 in my size.

 

[Glug]

I replaced the BB in a my 1961 Holdsworth Cyclone with a Tange 3922 (115mm).
But a thing to note is the Tange is symmetric, old BBs were probably not.
I measured the chain line and clearance on my 1982 Holdsworth Avanti (original BB) and copied that:



It turned out if I added a 3mm BB spacer to the drive side everything pretty much worked.
NB. don't tighten everything up before checking if it's scraping off your paint.

 

[FluffyChicken]

I replaced the BB in a my 1961 Holdsworth Cyclone with a Tange 3922 (115mm).
But a thing to note is the Tange is symmetric, old BBs were probably not.
I measured the chain line and clearance on my 1982 Holdsworth Avanti (original BB) and copied that:

View attachment 805243

It turned out if I added a 3mm BB spacer to the drive side everything pretty much worked.
NB. don't tighten everything up before checking if it's scraping off your paint.

Luckily here the Deore groupset is part of the switch over and the direct replacement for a D-NL is the 122.5 Shimano sealed, that is also market as a D-NL.

If you look in the big Sutherland 6th Edition you can see comparable bb and the different calc/offset list for many different BBs.

I can't remember but Barnetts may have something similar.

 

[cratecropz]

I’ll get the shimano un55. But which length? 115 or 127?