Plunger rear wheel in rigid frame.

[V500]

As the title says, has anyone fitted a plunger rear wheel into an earlier B31/33 rigid frame ? Does it take much modification? The earlier rigid rear hub seems to be thin on the ground.
Thanks.

[idie]

If you are referring to the QD splined hub I belive the ridged hub and the swinging arm arm hubs are much the same.

[limeyrob]

Can you get measurements of the spindle dia?  I have a vague recollection that the plunger spindle is larger but don't quote me.  Even if it is in may not be a show stopper as BSA may have used bearings with the same OD but large ID so you could swap bearings.
BSA do have form when it comes to tweaking bearing sizes, there's a right mix of imperial and metric on some hubs.

[Derek996]

As the title says, has anyone fitted a plunger rear wheel into an earlier B31/33 rigid frame ? Does it take much modification? The earlier rigid rear hub seems to be thin on the ground.
Thanks.

This something that I've considered for my ZB32, mainly because the sprocket is showing signs of wear and I don't know long it will last. New sprockets can be welded to the drum after machining the old one off but it will require dismantling and rebuilding the wheel, something I'd rather not have to do.
I know that it can be done but not sure what's involved. As Limeyrob says there is possibly a difference in spinde diameters. A custom spacer will be required on the RH side and since you will lose the cam adjusters that maintain wheel alignment some sort of chain adjustment will be required.

[limeyrob]

Is your brake drum / sprocket 65-6289?  If so these seem to be available.
Can you drill the rivets out and fit the new drum using the bolts/nuts for the later hub - 67-6038?  These are available and they must be up to the job as they bolt up the later drum/hub and I would assume that the heads / length mean they clear the shoes.

[Derek996]

The sprocket/brake drum for the rigid frames is part of the hub. It can't be replaced on it's own.

[limeyrob]

But is it rivetted?  It seems that the drum / sprocket could be replaced and re-rivetted.  Not uncommon at the time as the clutches were the same.  Often the drum / sprocket was cast and the hub / flanges are pressed.

[Derek996]

Yes, the brake drum is rivetted to the hub so technically it could be replaced by drilling out the rivets. Whether the 65-6289 drum can be fitted will depend on it's dimensions and I suspect new holes will need to be drilled to match the PCD of the rivets of the rigid hub.