Tire measurement meaning.

[drummerdude]

Can anyone explain the meanings of the numbers of the tire size... i know the R17 means the rims are 17 but can anyone explain the other meaning... like the width of the tire mainly.Thanks!

[ragingfish]

This should help: Quote, originally posted by Cooper Tire »Tire SizeThe tire size is written on the tire’s sidewall. Here’s an example of the way tire sizing looks on the sidewall: * P indicates a passenger (car-type) tire. Other options would be no P indicating metric sizing (essentially the same as P-sizing, which has its heritage in Europe) or LT for light truck. LT truck tires are designed for heavier loads and more rugged service conditions. * Width of the tire, in millimeters. The higher the number the wider the tire. * Aspect ratio — The height of the sidewall section compared to the width of the tire. Example: — If this number was a 50, then the tire section is half as tall as it is wide. Short sidewalls deliver crisp handling. Tall sidewalls give a smoother ride. For a specific tire width, the smaller this number, the shorter the sidewall. * Construction — R indicates radial construction. Unless you specify the other option, bias (which would have a D [diagonal] or B [belted bias] in this position instead of an R), you are purchasing a radial tire. * Wheel Size Designation — This indicates the distance across the “doughnut hole” of a tire, in simple terms. You must match wheel diameter and tire diameter. For example, a 15-inch diameter tire must only be mounted on a 15-inch diameter rim. A tire with a 15 size designation will not work on a 14" wheel, and vice versa. Improperly matching of wheel and tire size can cause serious injury or death during installation. * Service Description — Includes the load index (a number) and a speed symbol (a letter). About load index, remember: Keep the number the same as or greater than the original tires’ load index. That number stands for a specific weight-carrying capability. Key is that the higher the number, the greater load-carrying capacity. So keep the number the same or higher, because your tires are matched to the weight of your car. Never choose a tire with a lower load-carrying capacity than the original equipment tire size. More info here: http://www.coopertire.com/us/e...l.asp

[drummerdude]

Thanks Ragingfish... i swear gen vibe is the best site... too bad there isn't a gen site for all vehicles

[ragingfish]

Is it me, or does it make NO sense to anyone at all that DIAMETER is in inches, but WIDTH is in millimeters???

[joatmon]

Don't forget to check out KBJ's http://forums.genvibe.com/zerothread?id=7087

[ragingfish]

Excellent find there joatmon! I tried searching under "tire info" and nothing came up. Wonder why.Nick, I hate the new search, seems much less reliable than the old one. Just MHO though...

[joatmon]

that thread was on the recommended reading list

[NSimkins]

Quote, originally posted by ragingfish »Excellent find there joatmon! I tried searching under "tire info" and nothing came up. Wonder why.Nick, I hate the new search, seems much less reliable than the old one. Just MHO though...I just searched using "tire info" and found 3 threads (including joatmon's). Not sure.. but we're having it looked at.

[ragingfish]

Hmmm...perhaps it's me then.