Swing Arm differences

[Humble Pie]

Been looking and wondering , are the only real differences in swing arms through the years the different mounts for different chain guards ? or are there dimensional changes as well ?

[muskrat]

G'day HP,
                the '56-'57 for the Ariel type hubs have two different size holes for the axle. That's the limit of my knowledge.
Cheers

[scotty]

Humble Pie,

I'm no expert but here's my 2cents

I have both early and late swing arms in my bitsa box

Dimensionally I find them the same and both have been fitted to my A10 frame

One difference that I found with my basket case bitsa is the rear brake anchor strap location on the swing arm.

On the full width rear brake model  the anchor point for the brake strap is on the right hand side of the swing arm
On the 1/2 width rear brake model the anchor point for the brake  stay  is on the left hand side of the swing arm

HTH and may wiser blokes than me chime in.

Scotty

[bsa-bill]

one other little difference Scotty, for one year only apparently the rear brake had the lever pointing up on a different brake plate, so you need a different length of torque bar to keep the brake plate perpndicular, guess who has a spare torque arm in stainless

[duncan32bsa]

Hi Humble Pie,
I've had similar issue in switching from crinkle hub to full-width. (Don't ask why - it seemed like a good idea at the time). No-one could give me dimensions so I made my own drawing. I've attached a JPEG but if anyone is interested in getting the .DWG "Autocad" version (you can then extract all the dimensions), let me know and I'll email it. BTW I used Draftsight beta a free CAD package from Dassault. I could adapt the drawing to the earlier version of the swing arm if you are interested. No guarantee that my school ruler has accurately extracted the dimensions of course but it seems that BSA concerned about repeatability, either...
Regards
Gary

[duncan32bsa]

Hi All,
just to add to this, I've quickly run up a drawing variant of the opposite brake variant.
Gary

[Humble Pie]

Gary

Much thanks ,,they are both very helpful

Cheyenne

[duncan32bsa]

Hi,
I realized I left a small piece of the last drawing, so here it is complete.
Regards
Gary

[Humble Pie]

Hi,
I realized I left a small piece of the last drawing, so here it is complete.
Regards
Gary

That's odd mine has nothing on the right side ,,just the 2 on the left.

[trevinoz]

There is no cast brake anchor lug on the '54/'55 swing arm frame on the right side as drawn.
The brake anchor is on the left side as well as the chain guard mounts.

Trev.

[Rocket Racer]

Gary,
 those two drawings are exactly what I was after