2009 JEEP WRANGLER UNLIMITED Owners Manual

Temperature Grades
The temperature grades are A (the highest), B, and C,
representing the tire’s resistance to the generation of heat
and its ability to dissipate heat, when tested under
controlled conditions on a specified indoor laboratory
test wheel. Sustained high temperature can cause the
material of the tire to degenerate and reduce tire life, and
excessive temperature can lead to sudden tire failure. The
grade C corresponds to a level of performance, which all
passenger car tires must meet under the Federal Motor
Vehicle Safety Standard No. 109. Grades B and A repre-
sent higher levels of performance on the laboratory test
wheel, than the minimum required by law.