Perhaps it is time I stepped into this:
First, read my webpage on the Ford / Firestone situation a few years back.
Barry's Tire Tech - The Ford / Firestone ControversySummary: The problem was the tire, not Ford's inflation pressure specification.
Second, the pressure listed on the sidewall of a tire is a MAXIMUM - not a recommendation. The tire manufacturer does not know what vehicle a tire is going to go on, so they can not make a universal recommendation that could be printed on the sidewall.
Further, if you ask any tire manufacturer what they recommend for inflation pressure, they will point to the vehicle manufacturer's spec - the one on the doorframe.
