Porsche carrera gt-2004 Benutzerhandbuch

146

Practical Tips, Emergency Service

Uniform Tire Quality Grading 

Quality grades can be found where applicable on 

the tire sidewall between tread shoulder and max-

imum section width. 

All passenger car tires must conform to Federal 

Safety Requirements in addition to these grades. 

Treadwear 
The treadwear grade is a comparative rating 

based on the wear rate of the tire when tested un-

der controlled conditions on a specific govern-

ment test course.

For example, a tire graded 150 would wear one 

and a half (1-1/2) times as well on the government 

course as a tire graded 100.

The relative performance of tires depends upon 

the actual conditions of their use, however, and 

may depart significantly from the norm due to vari-

ations in driving habits, service practices and dif-

ferences in road characteristics and climate. 

Traction AA, A, B, C 
The traction grades, from highest to lowest, are 

AA, A, B, and C and they represent the tire’s ability 

to stop on wet pavement as measured under con-

trolled conditions on specified government test 

surfaces of asphalt and concrete.

A tire marked C may have poor traction perfor-

mance. 

The traction grade assigned to this is based on 

braking (straight-ahead) traction tests and does 

not include cornering (turned) traction, accelera-

tion, hydroplaning or peak traction characteris-

tics.