Agency Amends Snow Tire Requirements for Light Vehicles

 The National Highway Traffic Safety Administration (NHTSA) has amended the performance requirements for snow tires for vehicles weighing less than 10,000 pounds. Instead of testing snow tires at a speed of 75 mph (120 km per hour), manufacturers will be required to test them at about 68 mph (110 km per hour). The revisions amend a final rule issued in June 2003 to Federal Motor Vehicle Safety Standard (FMVSS) 139, New Pneumatic Tires for Light Vehicles. The final rule required tires to be subjected to endurance tests under various vehicle load conditions at a speed of 120 km per hour (approximately 75 mph) for 34 hours. After completing that test, the same tire must perform in a low-pressure test for an additional 90 minutes. After these tests, FMVSS 139 requires no visible sign of tread, sidewall, ply, cord, belt or bead separation, chunking, open splices, cracking or broken cords.

The current changes come in response to petitions for reconsideration of the June 2003 rule. The agency said it reduced the endurance and low-pressure performance test speeds for all PC and LT snow tires with load ranges of C, D and E because the tires are constructed differently from other tires.