Confusing tyre sizes

[MattW]

Does anybody know how to work out the overall height of a tyre when it is in a format like 222/75/r15

I want a tyre that is the same height as a 33 but narrower than 12.5"

[Steve F]

(222 * 0.75 / 25.4) * 2 + 15 = Tyre Diameter

222 in your example is the width, 75 is the percentage of the width that is the sidewall height (lower number less height in sidewall), divide this by 25.4 to get it in inches then multiply by 2 to get the amount of tyre height on the rim and add the rim height, 15" in this case.

So this one is 28.1 inches tall and 8.74 inches wide (222/25.4)

To get a 33 you'd need something like 305/75/15. that would be 33x12x15

Easy

Cheers
Steve

[MattW]

Thanks steve

[wildturkey]

online tyre size calc http://www.miata.net/garage/tirecalc.html

[Gojeep]

Have a chart with all the sizes on it on my speedo page.

[BLU-125]

A 285/75R16 in lots of brands or 33/10.50R15 if BFGs suit.

[MattW]

Yea it has to suit a 15" rim and BFG are shite. Will have to stick with a 33x12.5x15 i think