71.   Spare tires are another consideration.

72.   Taking two tires would have been stupid for us.

73.   That has made it hard for lawyers and others to calculate whether the tires are linked to an above-average rate of fatal crashes.

74.   The automaker has begun preparations to replace additional Firestone tires, although Firestone insists its tires are safe.

75.   The blown tire was a Firestone radial ATX, like millions of others now being scrutinized.

76.   The cars are slower, the engines have a little less power, the tires are somewhat tougher, and the track is worn down some.

77.   The chart also described how the tires were coming apart and the rates at which each type of separation was increasing.

78.   The company said the tire was old and worn and should have been replaced.

79.   The device triggers an alarm, warning drivers that although the tire is not actually flat, it has lost air and needs to be replaced soon.

80.   The difference has caught the attention of lawyers who sue tiremakers because tires are more likely to fail if they are used at lower pressures.