Dodge 2010 Ram - Manual (Page 587)

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.
WARNING!
The temperature grade for this tire is established for
a tire that is properly inflated and not overloaded.
Excessive speed, under-inflation, or excessive load-
ing, either separately or in combination, can cause
heat buildup and possible tire failure.
586 IF YOU NEED CONSUMER ASSISTANCE