• Dayton tires, made for passenger and light trucks, are manufactured by Bridgestone Tire Company. Dayton tires have certain specifications that you'll need to understand when searching through their product catalog. You'll be able to find out this information, represented by a series of numbers and letters, on the sidewall of the tire. You may see something like this: P205/70R15
  
  

Passenger or Light Truck

• The first characters on the sidewalls will be letters. These letters inform what type of vehicle the tires go on. "P" stands for passenger, and "LT" refers to light truck.
  
  

Tire Width

• Following the letters will be a three-digit number. This refers to the tire width in millimeters.
  
  

Tire Aspect Ratio

• Next you will see the aspect ratio of the tire. This number tells you the height of the tire in a percentage divided by the tire's width. You can think of it as the height of the tire divided by the tire's width.
  
  

Tire Construction

• The next section of information is known as the construction of the tire. The letter "R" refers to radial. Sometimes you will see a letter "B," which means bias. Bias tires are softer and can absorb more damage to the sidewall. Radial tires tend to last longer because of their harder construction type.
  
  

Tire Diameter

• The numbers the the construction letter refers to the diameter of the wheel the tire was made to fit. For example 16 is a common tire diameter; this means that the tire was made to fit a 16-inch wheel.
  
  

Load Index

• Sometimes, directly following the diameter info will be a two-digit number that refers to the tire's load index. The load index is the amount of weight the tire was made to support.
  
  

Speed Rating

• The speed rating is the letter that follows the load index number and tells you the maximum speed the tire was designed to operate. Different letters letters refer to different speed ratings. H in our case lets us know that the tire was designed for handle under 99 miles per hour.
  
  

Tires Age

• The DOT number or date of tire number is found at along the inside edge of the tire and lets you know that the tire meets federal guidelines and the age of the tire. The week and year the tire was produced is the last four digits of the DOT number.