I just want to clarify the difference between two types of brake drum bolts.
One set I have is square under the head, and the other set is tapered.
Brake drum bolts #66-6070 would fit hub #66-6067 M20 1946-48
Brake drum bolts #3355-30 would fit hub #3355-20 M20 1938-45
The drawings I have show squared
Can any-one advise which is which. Are the earlier bolts tapered.
Thanks keith
Pre- and early-war BSA,s used the flat bolts, the tapered version is an improvement introduced in 1942. It seems that nearly all BSA WM20's around today ended up with the tapered bolts / hubs.
Henk; Do you know if they altered the hole in the hub after 1945, to accept tapered bolts, or were they just left square?? Very hard to see on any drawings I have.
Thanks Keith
These change were made in 1942, I have a little booklet somewhere that mentioned the frame number for this change. I will be leaving for Crete in one hour, I can have a look for that little book when I am home again. I might have it digitally on my laptop then I will take a look at it sitting on Crete in the sun.
Hello Henk;
When you were sunning your self on Crete, and browsing your laptop, did you happen to come across any mention if there was difference in the holes on the rear hub to accept the squared bolts, or the tapered bolts.
Also, Is Crete coffee nice, flavoursome, and rich????
Thanks Keith
My 1942 WM20 has the flat ones,I believe the holes in the hub are different? the hole`s in my hub were out of round from the bolts working loose,the bike is very original and I never had another wheel to replace it, so I just centred them as best as possible and used loctite and never had a issue. tried it first without loctite but they worked loose in no time.I get a slight plusing when I push the rear brake hard [not centred perfect]but soon got used to it and the brake still pull`s the bike up well
I have a 43 surplus sale bike.
The rear hub painted Black over green has tapered holes.
It was also fitted with (Knackered ) tapered bolts so I am assuming it was the original fit ment.
Yes, Is seems to be easier to loosen off everything, and remove the wheel complete, that way you can check the linings as well. By the way, is there a dimensional drawing available anywhere, showing the lay-out of the six holes in the hub.
I have a hub with worn peg holes, I would like to have repaired.
Thanks Keith
