CarBuyersNoteBook

You ever look at the side (called the sidewall) of your tires and see all those letters and numbers?  Ever wonder what they mean?  Well, I’m gonna give you a quick primer to tell you what you’re looking at.

For instance, take this sample designation:

P235 /60R15 70s M+S

Seems unintelligible, right?  But we’ll fix that straightaway!

P: tire type.  In this case, “passenger”.

235: section width.  The width between sidewalls, expressed in millimeters.

60: aspect ratio.  Sidewall height as a percentage of cross-section width.  The shorter the ratio, the more useful the tire is in steering.

R: tire construction.  In this case “radial”, the most common.

15: rim diameter.  14 and 15 are most common.

70: load rating.  The maximum load rating of the tire, given as a quick reference and usually mentioned in full elsewhere on the tire.

S:  speed rating. The higher the letter, the higher the maximum speed.  The only exception to this is an H rank tire, which is actually the second highest possible speed rank below V rank.

M+S: mud and snow.  This is an all-weather designation.

And that is how you read a tire.