520
Uniform tire quality grading standards
Example 2B
For example , if a person weighing 143 lbs ( 65 kg ) and a child weighing 40 lbs ( 18 kg ) now enter the same vehicle ( bringing the number of occupants to three ), and a child restraint system weighing 11 lbs ( 5 kg ) is installed in the vehicle for the child to use , the calculations are as follows .
1 . Calculate the total weight .
2 . Calculate the available load capacity .
3 . The total weight now exceeds the capacity weight by 32 lbs ( 15 kg ), so the cargo weight must be reduced by 32 lbs ( 15 kg ) or more .
13-4 . Uniform tire quality grading standards
S13AC
This information indicates the relative performance of passenger car tires in the area of treadwear , traction , and temperature resistance . This is to aid the consumer in making an informed choice in the purchase of tires .
Quality grades can be found where applicable on the tire sidewall between tread shoulder and maximum section width .
For example :
TREADWEAR 200 TRACTION AA TEMPERATURE A
The quality grades apply to new pneumatic tires for use on passenger cars . However , they do not apply to deep tread , winter type snow tires , space-saver or temporary use spare tires , tires with nominal rim diameters of 12 inches or less , or to some limited production tires .