Owner's Manual
Page 302
... specified government test surfaces of heat and its ability to dissipate heat when tested under controlled conditions on a specified indoor laboratory test wheel. Grade C corresponds to a level of the tire when tested under the Federal Motor Vehicle Safety Standard No. 109. RX-8_8T69-EA-04G_Edition1... can cause the material of variations in driving habits, service practices and differences in road characteristics and climate. qTread Wear The tread wear grade is based on a specified government test course. Grades B and A represent higher levels of their use, however, and may...
... specified government test surfaces of heat and its ability to dissipate heat when tested under controlled conditions on a specified indoor laboratory test wheel. Grade C corresponds to a level of the tire when tested under the Federal Motor Vehicle Safety Standard No. 109. RX-8_8T69-EA-04G_Edition1... can cause the material of variations in driving habits, service practices and differences in road characteristics and climate. qTread Wear The tread wear grade is based on a specified government test course. Grades B and A represent higher levels of their use, however, and may...