“225/70 R16 91S.” It looks like some wild alpha-numeric code you’d find on the manufacturer’s label of your favorite gadgets.

R: Means radial, which is what almost all tires are these days ... Step 2: Check the Speed Rating and Load Index Right after the size, you’ll see something like "94H" or "102S." ...

The letters and numbers that follow, such as ZR17, provide additional information about speed ratings and whether the tire is ...