Furious Freds? Very light tyres - easy way to knock a pound off your bike, but as previously noted very fragile. I've not a problem with using modern tyres on a retro build. Sammy Slicks are a bit heavier but also more robust.
It was nice to take it apart piece by piece and reconstruct it 1993, components are the same, Now I use it to go to work but I would change it again ...