Car manufacturers like the tire pressure customized to their design.
For example, the old Ford Explorers rode like, well, a four wheel drive vehicle designed for off road use. In order to appeal to the suburban set, a slightly lower tire inflation pressure could be used in order to give a much smoother ride. Of course, that increased the tire temperature at high speeds and the Firestone tires that came factory installed tended to come apart if you drove with underinflated tires at high speeds on hot days.
In fact, Corvairs had a similar problem. They weren't very stable unless the tires were kept at the proper pressure for the car - a pressure that didn't necessarily match the tire manufacturer's recommendation. They didn't come apart, but the average driver would tend to fill the tires to the pressure stamped on the side of the tire, making the car "Unsafe At Any Speed".
Just in the interest of increasing my sex appeal, I should mention that Sunday, I changed the oil on both of my cars, plus my daughter's car ... and I've only accidently left the oil cap off once in my life. (I did that while cleaning splashed mud out of the interior of my Jeep - I hate it when oncoming traffic doesn't slow down for creeks

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