Maybe I read something about fluid dynamics in a catalogue years ago, then and presumed it meant they had fluid in them. I could only afford one of those stretch on Unidisc covers back then. I only chucked this about 18 months ago.
Back to the bike though. It's ready for a blast down the road now it's got a new front tub on. This is the first time I've fitted a tub and it was mega tight to stretch on. I fitted it dry and then left it at 170psi for three days to stretch. Then fitted it using Tufo tub tape which I found pretty easy. I've gone for a new Continental tyre which has black walls, so now I need a rear to match. The rear one is a silk Bis from 92 and is dropping to bits, but will be ok for a test ride down the road tomorrow night. Last time I rode this bike was 22 years ago so it might be a bit wobbly.