speed rating

The maximum driving speed for which a tire is designed, indicated by a letter in the tire designation on the sidewall. The speed rating evolved gradually and is thus not directly proportional to the alphabetical order.

P = up to 150 kph (95 mph)

Q = up to 160 kph (100 mph)

R = up to 170 kph (105 mph)

S = up to 180 kph (113 mph)

T = up to 190 kph (118 mph)

U = up to 200 kph (125 mph)

H = up to 210 kph (130 mph) also called "high speed" thus the "H"

V = over 210 kph (over 130 mph) also called "very high speed" thus the "V"