Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board Nuts!

I am building a B441VS from several boxes of bits i.e. I did not take this one apart! Originally built in March 1969.
Rear hub looks like the original QD.

Rear wheel NS (drive side) wheel nut is horribly tight. Looking at the thread on the stud the threads look a bit "flattened", not massively, but enough to make it a bit too tight. Running a die down it and a tap up the nut would sort it but I cannot find any documentation saying what size it is
I have all the usual suspects, ( UNF, UNC, Metric) but somehow I doubt any of these will suffice.

Bit of a "newbie" question I suppose but any ideas?

9/16" x 20 - American

many thanks!

Hi Dave,

Fwiw, I've come across similar on Triumph QD hubs:-

. 9/16"-20 is a bog-standard Cycle thread; otoh, common "American" 9/16"UNF is 18 tpi, 9/16"UNEF is 24 tpi. There is a Unified 9/16"-20 but it's one of what's known as the Constant Pitch series; ime, it'd be weird for a 1960's wheel spindle thread ...?

. Despite the same tpi at several relatively-large diameters, Cycle and Unified have different thread profiles; ime, one squeezed into or on to the other causes the "a bit "flattened"" and "horribly tight" symptoms ...

Parts book says it's left-hand ... However, before you pour flammable liquid over the bike ... search out a pushbike repairer; curiously, even modern pushbikes use 9/16" Cycle threads on the pedal crank, right-hand on one side ... and left-hand on t'other. Only thing that might rain on this particular parade is if the pushbike threads are 26 tpi (the other common Cycle pitch ).

Or Tracy Tools in GB has 9/16"-20 left-hand Cycle taps 'n' die.

Unless you can find a competent machinist with a lathe that can screw-cut ...

Hth.

Regards,

yeah, says left hand on my Parts book as well ...... trouble is it isn't, and neither is the one on my other B44! Parts book wrong?

will try to a 9/16 20 tpi tap and die.

Hi Dave,
Right-hand thread are bit cheaper, even in HSS.

Hth.

Regards,