I posted this on edmunds for educational purposes of young drivers (you older folks already have your minds made up)

Manufacturers design the tires to match up with the cars. They expect a specific tire surface interface area on the pavement to create a desired safe handling characteristics.

Just because a tire has a maximum pressure rating does not mean it should be achieved. If you put the same tire on a 3500# car and a 4400# car you'll want more pressure in the heavier car to create the right surface area. Increasing the pressure on a lighter car however lessens the tire contact area and thus create a longer braking distance as well as less surface area for grip.

Granted there is some "play" in these numbers but increasing pressures 30% over design is pushing the safety and handling aspect of the tire design for good FE.

Tires are designed with a maximum pressure so that they can achieve a wide range of applications, not so you can pump them up hard on your TCH.

Also (someone mentioned the max on the Michellin was 44 psig) running at 42 cold pressure on concrete highways at high speed in hot weather will probably exceed your maximum tire pressures. If you blow a tire and wreck your car don't put it past your insurance or whoever you decide to sue to check your pressures on your other tires or for that matter your comments on this website to see if you purposely exceeded recommended pressures. (I'm not a lawyer, just spend a lot of time tring to figure them out at times)

I realize this won't change the minds of you die hards. Don't even want to. However many novices watch these forums for ideas and "buy into" just about everything they read from synthetic oil, high tire pressures and running in neutral. All these things should be (re)considered after research and study, not just as a "I wanna do it to" attitude.