Nascar Tire Evolution by Tom Mooty via Randy Ayers Board

[Tom Birky]

This is copied and pasted from the web archive of the old board. It was originally posted by Dr. Craft:

"1965 was a big year in Grand national tire technology. Small letter Goodyear "Blue Streaks" with a "70" series profile (more squared off shoulder relative to tread) showed up that season. Prior to '65, racing Goodyears were more of a "78" series profile and did not have a racey blue stripe. After the blue streaks appeared, the Goodyear sidewall stayed pretty much the same (compound and tread pattern varied but sidewall did not) through the 1969 season. In 1970 the blue streak got 86ed and the Goodyear lettering grew to what I call three quarter size (compared to today's logo). Tire diameter and tread size also increased. Firestones followed a similar evolution. Prior to '65 Firestone "Darlington" gum dipped tires featured a "78" series style profile a small white Firestone logo and no "stripes". Firestones did feature a small crossed flag Firestone crest water transfer decal on their sidewalls. Early decals were white and later decals (ie '64 through early '65) were red and white (these will be very hard to capture in scale). In '63 side wall embossing changed from Darlington to Stock Car 500, then Stock Car 600 and finally in early 1965, Stock Car 800 (I had to find a set of these partial year unobtanium tires for my Daytona car--very expensive, made me wish I was a rich footbal coach/teacher at the time!). This embossing was NOT white letter however. I only mention it for reference. About mid year, the crossed flag decal was ditched and a gold Line was added to the side wall of the Firestone tires. It is important to note that at the same time the Firestone lettering went from white to GOLD to match the gold line on the side wall. This is a common modeling mistake I have noticed. The tires also became more "70" series in profile. Firestone sidewall configuration stayed pretty much the same unti the company dropped out of the series in the late sixties. Firestones were treaded until then. Oh, BTW, tire size was nominally 8.00/8.20 x 15 all through the sixties. That said ,actual tire size varied greatly over that period. Early 60s tires were nearly 30" tall and had about 8" of tread. By the end of the decade, height had dropped to about 27" and tread width had grown to 10". Hope this helps out."