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AMT PP034 Firestone Wide Oval Tires


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I'm not a muscle  car expert, but I knew (mainly from looking at various model kit tire markings over the years) that back in the day tire markings were different than they are today. Plus the different numbers were mentioned on the box.

Quoting https://en.wikipedia.org/wiki/Tire_code

Prior to 1964, tires were all made to a 90% aspect ratio. Tire size was specified as the tire width in inches and the diameter in inches – for example, 6.50-15.

From 1965 to the early 1970s, tires were made to an 80% aspect ratio. Tire size was again specified by width in inches and diameter in inches. To differentiate from the earlier 90-ratio tires, the decimal point is usually omitted from the width – for example, 685-15 for a tire 6.85 inches wide.

Starting in 1972 tires were specified by load rating, using a letter code. In practice, a higher load rating tire was also a wider tire. In this system a tire had a letter, optionally followed by "R" for radial tires, followed by the aspect ratio, a dash and the diameter – C78-15 or CR78-15 for bias and radial, respectively. Each diameter of rim had a separate sequence of load ratings; thus, a C78-14 and a C78-15 are not the same width. An aspect ratio of 78% was typical for letter-sized tires, although 70% was also common and lower profiles down to 50% were occasionally seen.

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2 hours ago, peteski said:

I'm not a muscle  car expert, but I knew (mainly from looking at various model kit tire markings over the years) that back in the day tire markings were different than they are today. Plus the different numbers were mentioned on the box.

Quoting https://en.wikipedia.org/wiki/Tire_code

Prior to 1964, tires were all made to a 90% aspect ratio. Tire size was specified as the tire width in inches and the diameter in inches – for example, 6.50-15.

From 1965 to the early 1970s, tires were made to an 80% aspect ratio. Tire size was again specified by width in inches and diameter in inches. To differentiate from the earlier 90-ratio tires, the decimal point is usually omitted from the width – for example, 685-15 for a tire 6.85 inches wide.

Starting in 1972 tires were specified by load rating, using a letter code. In practice, a higher load rating tire was also a wider tire. In this system a tire had a letter, optionally followed by "R" for radial tires, followed by the aspect ratio, a dash and the diameter – C78-15 or CR78-15 for bias and radial, respectively. Each diameter of rim had a separate sequence of load ratings; thus, a C78-14 and a C78-15 are not the same width. An aspect ratio of 78% was typical for letter-sized tires, although 70% was also common and lower profiles down to 50% were occasionally seen.

This thread is getting funny, but I remember this sticker in the glovebox of my '68 Mustang. My '68 Cougar probably had a similar one, but I don't remember.

Decal Tire Pressure Door Late 68 1968

Edited by Rodent
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