[Buddy Rawls]

FIA cars used 6.5 and 8.5 wheels, with 6.70x15 and 8.20x15 speedway special tires. when I research those sizes for old racing tires, they come out narrower than 235-60 and 295-50 typical go-to sizing. They came out closer to a 215-70 and 255-60. I know the 6.00x15 and 7.00x15 GY Vintage Sports Car tires shows much wider, but there is no way those could fit properly on a 6.5/8.5 set-up. they do fit well on the 7.5/9.5 set-up. what's the real story? does anyone have a early 60's race tire catalog?

Is 6.70 designation the tread width? meaning sidewall is around 8.5-9 in wide bias designs. perfect for 6.5 wheel.
Likewise the 8.20 tread would have a sidewall around 10-11 in wide, again perfect for a 8.5 wheel.

Just throwing it out there for continued discussion.