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Reverend Trick Playa
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Anybody point me to a web site for actual tire size conversions (in inches) from the metrics.......i.e., what size tire is a 35" with a 17" rim? Is it still a 305x75x17?
 

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i was told that in p metrics that the size of the tire is all different depending on what size rim, and the width is a % of the overall height, im just throwing that out there in case u didnt already know
 

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Sway Is My Fan Club.
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quiefinator said:
i was told that in p metrics that the size of the tire is all different depending on what size rim, and the width is a % of the overall height, im just throwing that out there in case u didnt already know
Yeah, I don't remember how it works, but it'll look different. Like those Mastercrafts I want, don't come in a 33, but they have a metric that's "similar" but will still look small or be smaller because of the aspect ratio and what not.

But here, this is the best one I've found -

http://www.redrock4x4.com/tech/tire_calc.php
 

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a 305/75/17 would indicate a tire that is 305mm wide and has a side wall (aspect ratio) of 75% of the 305MM width.....the 17 is the OD of the rim or the ID of the tire..................no?

I am sure if you search you can find tooooo much info on this sort of stuff.
 

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gang, your right the 305 is width and the 75 the sidewall height that is 75% of the 305mm width
 

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To convert the metric numbers into (nominal, not exact) inch dimensions (using a 235/75R15 as an example)

Nominal section width = metric section width / 25.4
ex: 235/25.4 = 9.25"

Nominal height = (section width * aspect ratio / 50) + rim diameter
ex. (9.25 * 75 / 50) + 15 = 28.875"

Compare that with the Tire Rack specs for a 235/75R15 (specifically the ones I just pulled off my Bronco). Section width = 9.4", total diameter = 28.8". Close enough to compare, and the formulas are pretty easy to remember. The difference in real numbers is due to the metric size being approximate, not to an error in the formula.
 

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