Ford's decision to outfit Explorers with tires with the lowest temperature threshold baffles tire and safety experts. B's OK, but even on my car, the first thing I look for is an A rating before I buy a tire. I wouldn't put any of that cheap stuff on mine. Likewise it is the tire maker's responsibility to evaluate and rate a tire's temperature grades. Clarence Ditlow, head of the National Center for Auto Safety in Washington, said he does not buy that explanation.
Some analysts suggest that the vehicle's sheer profitability is a factor.
The selection of C-rated tires may have been exacerbated by Ford's recommendation that owners inflate the tires to 26 pounds per square inch, lower than Firestone's recommendation of 30 psi. Ford's promoting of a lower tire pressure than recommended by the tire maker has become a central issue in the failures, as lower inflation causes greater friction and thus heat buildup. I was surprised to find that Ford itself was willing to buy a tire with a C rating. It's going to increase the percentage of failures of that tire over time. Since the recall of the 6.5 million Firestone tires on Aug. 9, Ford had maintained that a range of 26 to 30 psi is acceptable.