my tyre pressure versus fuel economy test.

[Mickey_M]

Increasing tire pressure decreases rolling resistance. In the days of the "Mobil Gas Economy Run" the teams ran 80psi and up.

The sidewall pressure rating is cold. If you take it to 44psi, a common rating, and the tire itself goes to 46psi when heated, you're still okay.

Generally with radial tires there is little increase in diameter as you raise tire pressure. You can, if you push it too far, get some uneven tire wear (wear out the center of the tread), but you have to push it pretty hard to do it.

 

[STSinNYC]

Wantin150, we kept the MXV4+ tires on our 02 Accord V6 at 40 PSI (cold max 44). Rotated every 6-8 K miles. At 69.4 K miles, we still had enough tread to pass inspection, and we did not see greater wear in the center vs. the edges. If the contact patch had been reduced, it wasn't visible. Perhaps a 3-3,500 lb. car places enough pressure on the tire to keep it fairly flat at 40 PSI.