You may well be right, but like you say it was a long time back. For some reason after I wrote my reply, I starting thinking that I'd got it wrong and it was actually called a 'Roadmaster', or am I now confusing this with a 'routemaster'? bus that is. Don't you hate getting old!I think you'll find the "Speedmaster" of the 60's 70's was a front tyre which was quite "rounded". Popular rears were the "Universal", which was squarish, but became more rounded, then came the Safety mileage, which was quite rounded from the start.
I think! Long time ago.