1993 Cadillac Fleetwood Owner's Manual - Page 311

If you ever replace your tires those nothaving a TPC Spec number, with make sure they are the same load range, speed rating and size, construction type (bias, bias-belted or radial)as your originaltires. A CAUTION: Mixing tires couldcause you to lose control, while driving. you If mix tires of differentsizes or types (radial and bias-belted tires), the vehiclemay not handle properly, and you could have a crash. Be sure to use the same size and type tires on all wheels. It's all right to drive with your compact spare, though. It was developed forlimited use on your vehicle. I i Ungorm Tire Quality Grading The following information relatesto thesystem developed by the United' States NationalHighway Traffic Safety Administration which grades tires by treadwear, traction and temperature performance. applies only (This to vehicles sold in the United States.) I Treadwear The treadwear gradeis a comparative rating based thewear rateof on the tirewhen tested under controlled conditions a specified on government test course. For example, a tire graded would wear one 150 and ahalf (11/2) times as wellon the government course as a tire graded 100. The relative performance tires depends upon the actual of conditions of their use, however, and may depart significantly from the norm due to variations drivinghabits, service practices anddifferences in in road characteristics and climate. r . F . J Traction - A , B, C The traction grades, from highest to lowest are: A, B, and C. They represent thetire's ability to stop on wet pavement as measured under controlled conditionson specified government test surfaces asphalt of concrete. A tire markedC may havepoor traction performance. ! I I