The speed rating designates the tire’s capability to withstand excessive speed.
The letter H denotes the tire has a 130 miles per hour (mph) speed rating. Other speed ratings are:
Q – 99 mph
S – 112 mph
T – 118 mph
U – 124 mph
V – above 130 mph short of service description
V – 149 mph with service description
Z – above 149 mph
Speed ratings are based on laboratory tests, and these ratings are not authentic if tires are worn out, disfigured, modified, underinflated, or overloaded. The condition of the automobile may also affect high-speed operation.