Each tire has a letter reating to determine the top speed a tire can reach, before losing traction. The chart is as follows:

M 81 mph 130 km/h
N 87 mph 140 km/h
P 93 mph 150 km/h
Q 99 mph 160 km/h
R 106 mph 170 km/h
S 112 mph 180 km/h
T 118 mph 190 km/h
U 124 mph 200 km/h
H 130 mph 210 km/h
V 149 mph 240 km/h
W 168 mph 270 km/h
Y 186 mph 300 km/h

Taking a look at some of Nitto's tires:

Nitto 404
275/65/R17 115V

That last character, the "V" means it is a V-rated tire. Using the chart, that makes the gives the tire a maximum speed of 149mph 240km/h.

Use the tire ratings to determine if the tire's top speed is right for you
by BringMeASunkist September 21, 2006
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