For those who may not realise it, most centre-lock wire wheels cannot be balanced on the standard dynamic balancers found in every tyre depot in the country. These use a choice of flat plates or conical adapters to centre the wheels, and rely on the central holes though the wheels being accurately machined to be concentric with the wheel. This works OK for the inside of centre-lock wires which are seated on a conical section of the wheel hub, but the outer machined surface of the wheels are inverted conical sections which mate with the inside of the spinner.
With the exception of Dayton wheels, the inside of the hole through the wire wheels is not accurately machined to be concentric, and mounting these on the normal cones will result in inaccurate balancing. Special adapters are needed, which the balancer machine manufacturers do make, but which few tyre places will have to hand.
I found a writeup on the web of someone who had made an adapter by using an old hub and spinner, so I decided to do the same. I had kept an old hub when I did my rebuild, and I picked up an old, battered spinner. I had a local machinist cut off the outer splined section of the old hub,
and machine a concentric 60mm hole through the middle of the spinner.
I then had an adapter which slips into the splined section of the wheel from outside, and allows a normal balancer conical locator to accurately centralise the wheel.
So I went to my local tyre depot today, had the wheels balanced using the adapter (both were miles out of balance) - and the car is now smooth as whipped cream up to 90 and beyond.