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1977-78 NASCAR tire sizes

 
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DoctorLarry



Joined: 08 Mar 2019
Posts: 32

PostPosted: Thu Feb 20, 2020 9:39 am    Post subject: 1977-78 NASCAR tire sizes Reply with quote

Were all tire sizes standardized in the late 1970's? From what I can find now it is a 28/10-15 Goodyear. What about earlier, say 77-78?
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odcics2



Joined: 09 Feb 2018
Posts: 283

PostPosted: Tue Feb 25, 2020 2:32 pm    Post subject: Reply with quote

8.00/8.20-15 was the size listed on the sidewall for years, from the 60s forward..

The tires were different sizes physically over the years, but all had the same markings.

Hmmm, when did they change?
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AdamtheWayne



Joined: 09 Jul 2018
Posts: 1182

PostPosted: Tue Feb 25, 2020 3:19 pm    Post subject: Reply with quote

In 1965 a maximum rim width was set at 8 and a half inches. In 1970 the sidewall was set at 12.1 inch standard and the wheel width at 9 and a half inches.

Quoting from Bill Coulter's "Cars of the King".
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john843



Joined: 28 Jan 2018
Posts: 607
Location: S.C. Lowcountry

PostPosted: Tue Feb 25, 2020 4:04 pm    Post subject: Reply with quote

Another thing to keep in mind is that the "same" tire came in a variety of circumferences. I've selected and mounted a ton of racing tires over the years and even though you were buying 4 say, D35 track spec tires, they came in circumferences (determined by mounting them at 40 lbs. at the factory) usually ranging from around 82" to 87 and 3/4 inches. If you wanted to run 2" of stagger across the rear, you would get an 86 and an 84 They were almost always marked in 1/4" intervals but occasionally 1/2". We even found that by playing with the sizes overall, you could essentially tweak the gearing.
5 or 6 inches in circumference doesn't sound like a whole lot but it is very noticeable. When we completed our last asphalt Late Model and took it out to the lake behind the shop to photograph it, it didn't look nearly as "aggressive" with 82's as it did with 86.5's or 87's.

John
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