2000 Saab 9-5 Owner's Manual - Page 200

200 Car care and technical information Traction WARNING The traction grade assigned to a tire is based on straight-ahead braking, traction test and does not include acceleration, cornering, hydroplaning or peak traction characteristics. The traction grades, from highest to lowest, are AA, A, B and C. These grades represent the tire's ability to stop on wet pavement as measured under controlled conditions on specified government test surfaces of asphalt and concrete. A tire marked C may have poor traction performance. SG840 Uniform Tire Quality Grading (US) 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 Treadwear The treadwear grade is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified government test course. For example, a tire graded 150 would wear one and one 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 variations in driving habits, service practices and differences in road characteristics and climate. Wear indicators Wear indicators The tires incorporate wear indicators in the form of smooth, treadless strips across the width, which become visible when only 1.6 mm of tread remains. As soon as the indicators become visible, new tires should be fitted without delay. Make sure you are familiar with the legal limit for minimum tread depth in your country and also any regulations governing the use of winter tires.