2007 Lexus GS 350 Owners Manual - Page 468

4-3. Do-it-yourself maintenance n When to replace your vehicle's tires Tires should be replaced if: l You have tire damage such as cuts, splits, cracks deep enough to expose the fabric or bulges indicating internal damage l A tire goes flat repeatedly or cannot be properly repaired due to the size or location of a cut or other damage If you are not sure, consult with your Lexus dealer. n Replacing tires and wheels If the ID code of the tire pressure warning valve and transmitter is not registered, the tire pressure warning system will not work properly. After about 20 minutes, the tire pressure warning light comes on after blinking for 1 minute to indicate a system malfunction. n Tire life Any tire over 6 years old must be checked by a qualified technician even if they have seldom or never been used or damage is not obvious. n If the tread wears down below 0.16 in. (4 mm) on snow tires The effectiveness of snow tires is lost. n Low profile tires (245/40R18, P245/40R18 and 245/40ZR18 tires) Generally, low profile tires will wear more rapidly and tire grip performance will be reduced on snowy and/or icy roads when compared to standard tires. Be sure to use snow tires or snow chains on snowy and/or icy roads and drive carefully at a speed appropriate for road and weather conditions. 394