tire sizing question

[sickntwstdtoy]

sorry in advance for my ignorance on this subject.
how much larger in diameter/width are 215/60/15's than my 225/60/14's
thanks guys these tire numbers i always screw up
russ

[Carlos Brown]

Russ,

Here we go with tire sizing 101 which will allow you to perform most of the necessary size calculations.

1a.) Section width in mm to section width in inches ( 225 / 25.4 = 8.86" )
1b.) " .................................................. ..........." ( 215 / 25.4 = 8.46" )

2.) Side wall height = section width x aspect ratio / 25.4.

a.) ( 225 x .60 ) / 25.4 = 5.31 inches.
b.) And for the 215x60 = ( 215 x .60) / 25.4 = 5.08 inches.

3.) Tire height = (( Section width x aspect ratio x 2 ) / 25.4 ) + Rim height

a.) ( 225 x .60 x 2 ) = 270, (270 / 25.4) + 14 = , 10.63" + 14" = 24.63 inches.
b.) And for the 215x60x15 = (215 x .60 x 2 ) = 258, (258/25.4) + 15 = 10.16" + 15 = 25.16 inches.

I hope that is not too messy, good luck!

Regards,

Carlos

[jefe_not]

And if you're still wondring, try Google and tire size calculator. the first hit is often the Miata site.

http://www.miata.net/garage/tirecalc.html

It lets you put in the various sizes and see what affect it's got on your speedometer.