quote:
Originally posted by CapriRacer:
Just to make sure everyone has the facts.
The tire size was P235/75R15 and the pressure spec from Ford was 26 psi. Firestone's argument was that at 26 psi the load capacity of the tire was exactly equal to the maximum vehicle design load. IMHO this is just poor engneering practice, especially considering that it was well know that folks don't pay attention to their inflation pressure. Ford has since gone to larger tires in all its trucks and SUV's (some cars and inivans as well!) So I guess they must agree, even if its a secret to be kept from the lawyers.
But there's another reason not to use an inflation pressure lower that what is on the placard - vehicle handling.
All vehicles are tested at the inflation pressure listed. Over and over again by lots of different people.
If one were to lower the inflation pressure, the reaction of the tire (and therefore the vehicle) to steering input is slower. This might make the difference when avoiding the kid running into the street. It's these emergency situations where you have to trust the engineers who design and test these things. They get paid to put themselves in these situations and see how the vehicle reacts and if they find a problem - fix it (if they can!).