sefton1275gt
Devout Dirtbag
Also, there seems to be countless lock rings on sjs
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.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.