My turbo uses my 20 year old road bike.

The rear Campagnolo hub has just given up after 20 years of never being serviced, in fact I think the the cones are seized. Plus the fact it’s well out of truer.

It’s got an 8 speed Campagnolo cassette, so I assume I need a Campagnolo specific free hub?

Where can I get a cheap wheel, purely for turbo use?

Ta

You may struggle to get a wheel that will take an 8spd campag cassette. Uses a different spline pattern to modern Campag.

Ah great!

So I assume the next step is wheel with Shimano cassette off ebay?

Trouble then is that it’s original chain and chainset, and of course that won’t work with some one else’s shimano block…

Shimano 8spd cassettes are a different spacing to Campag 8spd so pretty tricky to index nicely I’d imagine…

Campagnolo
8-speed (centre-centre spacing, sprocket thickness, spacer thickness, total width) 5.0 mm 1.9 mm 3.1 mm 36.9 mm

Shimano 8 speed (centre-centre spacing, sprocket thickness, spacer thickness, total width) 4.8 mm 1.8 mm 3.0 mm 35.4 mm

(from Sheldon Brown)

for what its worth in case you have some campag 10 speed sti lying around, they shift very well with 8 speed shimano.
thats what my cx is currently running, crc have sram pg850 cassette for about £12.
cheaper in germany..