so..

I must be missing something. What numbers?

I sure hope you're missing something because If your not, I am..

;)



umm... things like 255/35ZR-18??

Originally posted by Adam
I sure hope you're missing something because If your not, I am..

;)



umm... things like 255/35ZR-18??

The first number has to do with the width of the tire. From the outside to inside.

The second number, has to do with tire profile meaning from the edge of the rim to the outside part of the tire.

The letters are the speed rating of the tire.

The final number is the size of the rim it fits.

i see isee

255/35ZR-18


To be a little more specific:

255 = Width of tire in millimeters

35 = aspect ratio in percent (35% means the height of the tire is 35% of its width. In this case 35% of 255mm = 89mm

Z = speed rating , in this case 149mph

R = Radial Ply tire

18 = rim diameter in inches

Don't ask why some is in mm and some in inches...

it is explained really well on www.discounttiredirect.com
and, on the aspect ratio, i believe it is the distance from the rim to the ground, not including the bead... but go to the site, and they give you all the technical shiet...

Man, its in inches and millimeters to Confuse you!!

more speed ratings:
Q=99mph
S=112mph
H=130mph
Y=189mph
Z=149mph+

There are more, I may poste them later.

Most tires are S rated. (family cars anyway)