H speed-rated tires are tested reliable at speeds up to 130mph, while V speed-rated tires are tested reliable at speeds up to 149 mph. Speed ratings are universal through all brands of tires.
The five most common speed ratings for commercially produced tires are T, H, V, W and Z. T-rated tires are the lowest on the spectrum of the common speed ratings with a maximum speed of 118 mph and are most commonly found on family sedans and minivans. Z-rated tires, however, can mean two different things depending on the manufacturer of the tire. Z-rated tires represent either a maximum speed of more than 149 mph or a maximum speed of 186 mph.