As long as I've been driving (30 years) I've used the max tire pressure value on the sidewall as the guide to proper inflation. I endeavor to keep the tires at that pressure. For the last couple years I've been getting my Frontier's oil changed at the local Jiffy Lube. I've realized that they're taking a value for optimum tire pressure from the door jamb of the driver's-side door. This value's about ten PSI lower than the max on the tire. They keep wanting to let air out of the tires to meet this "optimum" pressure. I think the car handles poorly at that pressure. I've been assuming that number in the door jamb is in error, since it doesn't match the max on the tire (though these are the original tires put on the truck by Nissan). The manager at Jiffy Lube points out that the max on the tire is the max, not the ideal, and that there are benefits to be gained by using the published "optimum" pressure.
What's the deal? Are they right? Should I be using the number from the door jamb, not the max on the tire?
Thanks,
-Scott