What would these two tire sizes convert to by today's tire standards:

7.50 x 14"
9.00 x 14"

Thanks
Tom

best guess with todays tire sizes (78/80 series tires would be closer match height-wise)


7.50 x 14 - 205/75/14

9.00 x 14 - 235/75/14 (good luck finding that much sidewall)

If you know which speedometer pinion and axle you have, you can calculate the correct size tire to keep your odometer accurate. I've written a page about this on the ACCCC web site. See the following page:

ACCCC Tire Upgrades

You could also consider upgrading to 15" tires while you're at it.

since this is the second time you have posted this advice .......

I would think the importance of speedometer pinion/rear axle ratio being the "driving" factor in tire selection to be very minimal in the mind of a car enthusiast. Most often the tire/wheel combination is about a "look", changing the speedometer pinion to allow the speedometer to read accurately is a cause of tire selection not the other way around.

BTW - the article is a good read, has good information in it but suggesting this early a-body tire solution is comical. What corner(s) are you going to put this tire on?

Quote:

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Because larger tires are easier to find that smaller, we can replace our orange 17-tooth speedometer pinion with a 16-tooth brown gear. Without changing the 2.93:1 axle gear ratio, our new corrected required tire diameter is 26.64" and would allow us to use a P225/70R15 tire (26.4" calculated static diameter). This would make our odometer record 0.9% more miles than actually driven.

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Recalculate your 225/70/15, isn't it closer to 27.4"?

Since FC7cuda inquired about modern equivalent-sized tires, I thought the tires mentioned were listed on his tire placard. Therefore, I thought that he was looking for an OEM-size tire without changing pinions.

Thanks for reading the article and for finding a typo. I meant to write P225/70R14 and I've made that correction.

Since I have a 1965 Barracuda of my own, I just used those tires as an example for the math. I suppose I could have used a later model as an example but I thought that the older cars originally equipped with 13" tires would be more likely to be facing problems finding replacement tires. I'm not sure why this would be comical.