1966 A65 Lightning Rear End Detail

[Kevev]

During the rebuild of my 1966 A65 Lightning I have been paying a lot of attention to the geometric detail and wheel alignment etc.

I have come across a little bit of confusion over the wheel rim offsets, more so on the rear wheel.

According to information I have gained on here, specifically a BSA document that Beach posted, I have a conflict between what the factory says and what I have measured on the rear wheel before I stripped it down.

The document that Beach posted says that the quick release 8" half width type brake drum front wheel rim should have an offset of 1-15/16" from the edge of the brake drum to the centre of the rim. My wheel was within 40 thou of that, so I am happy with that one.

The document says that for the Q/D rear wheel the rim should be central to the Q/D hub spoke flanges. That would give an offset from the edge of the speedo drive side hub spoke flange to the wheel rim of about 3mm. My original Wheel measured 7.5mm. Unfortunately, I did not check how central the original wheel was in the swinging arm and frame before I stripped the bike down.

If I was to aim for the factory offset dimensions, then the complete wheel assembly would need to move over to the final drive side by about 3.5mm.

I have checked the dimensions of all the spacers and associated parts and brand-new wheel bearings have been fitted. The only thing I am not sure about is the 68-6067 dummy wheel spindle dimensions, as I have nothing to reference this with.

With the rear brake assembly mounted in the frame, when I fit the bare Q/D hub assembly (without the rim and spokes) into the brake drum it does not seem to go in far enough and it also 'wobbles' a little when I press it home. Suggesting that the end face of the 68-6067 dummy spindle is not square to the wheel bearing inner race that it bears against? This also ties up with what I believe about the rear wheel needing to move over more that way.

Would it be possible for someone to measure the gap between the rear Q/D crinkle hub spoke flange and the rear brake drum driving flange, as shown in the attached image. This may help to confirm what I think that the rear wheel does need to move over a little more that way.

My rear brake has the steel brake plate, not the later alloy one and I am not sure if this is important, or not for this dimension?

Thank you

Kev E