At the end of a tire size like 205/55R16 91V, the 91 is the load index and the V is the speed rating. Both matter for safety, and you should never buy a tire rated below what your car needs.

Load index

The load index is a code for the maximum weight one tire can carry when properly inflated. Higher number means more capacity. For example, 91 is about 1,356 lbs per tire, and 95 is about 1,521 lbs. Your car's recommended load index is on the door-jamb sticker; match it or go higher, never lower.

Speed rating

The letter is the maximum speed the tire is designed to sustain. Common ratings include:

• T up to 118 mph
• H up to 130 mph
• V up to 149 mph
• W up to 168 mph

Speed rating is really a measure of the tire's build and heat resistance, so a higher-rated tire often handles better even at normal speeds. Match your car's original rating or higher.

Can I mix ratings?

Keep the same load index and speed rating across all four tires where possible. If they differ, your car's safe limit is set by the lowest-rated tire on it.

Find the right rating

Every Treadfy listing shows the load index and speed rating in the specs. Browse all tires or enter your size on the home page to see options that match your car.