Tire Pressure On Larger Tires?

[TennesseePA]

The suggestion that modern tires will be taller in the center than they will on the outside is a myth. Below the tread of a modern radial tire are steel belts. The belt layers are applied At. 90 degree angle to the direction of travel with reinforcing cords between the multiple belt layers. The construction of the tire keeps the tread surface flat regardless of the height of the sidewall. This is why the “chalk test” has such a wide range of success, modern tires make the test obsolete. The pressure you choose should be based on driveabity and nothing else. Tire pressure that is too low will cause a soft or wushu washy feeling and pressure that is too high will produce a harsh ride, loose steering and bumpsteer.

The max tire pressure molded into the sidewall, as stated before, is for operating the tire at it’s maximum rated capacity, not the maximum pressure that the tire can withstand. Don’t believe me? Go to the tire shop of your choice and see just how much pressure is needed to set the bead on a tire. Tire company executives and engineers like a steady paycheck just like us so they build their tires with a very wide safety margin to keep themselves and their companies out of court. Just ask Firestone, the delamination issue they had with their ATs that came on Ford Explorers almost bankrupted the company. Lots of finger pointing that Ford had the tire pressure too low but it was within space for the tire, it was a Firestone problem not a Ford problem. I know this because Firestone quietly replace all 5 tires on my Ranger which was supposed to run 35 or so on the rears.

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[ShadowsPapa]

Everyone I ask has said run my wife's GC tires at 36 - dealer and tire shops,. So we do. Always fine. They wear fine, evenly, it rides and handles fine. I run my Javelin radials at 30-32, always have, both of them before I sold one. Similar for my SX4 - 30-32

Over-inflation pushes the center of the tire out. Like a balloon, this can be proven. (see below)
Under-inflation pushes the middle in, wears and heats the sidewalls due to excess flex.
Want some deep scoop? Two of my wife's cousins worked most of their lives at Firestone, later Bridgestone. One a tire-maker on the floor, the other in some sort of control office.

(below)
That test I mentioned for weighing your car using only the tires (and 4 pieces of paper or cardboard, a pencil and a ruler) - that proves that as you increase pressure in the tire, the middle pushes out and lifts the tire off the ground.
Here's how it works - you lay large sheets of paper in front of, behind, to the inside of, and the outside of one of the tires. The paper should overlap. Sort of form a box around the tire with the paper.
Put pencil marks on the paper where they overlap - so you can remove the paper from around the tire and reassemble your "square".
Remove the paper from around the tire, reassemble them on the floor or a table and line them up exactly as they were around the tire. Now measure the square in the middle - that's the foot print of the tire. Figure the square inches of that area.
Measure the air PSI of that tire - for example, if it's 35 psi, take 35 times the square inches of the square made by the paper.
Do this for each tire - surround the tire with the paper forming a square around the tire. Figure the tire footprint using that paper, figure the square inches, then take the pressure in THAT tire times the square inches of that footprint.
Add them all up - should be about what your car weighs.
35 psi in a tire, say the paper measure was 6" x 5" for 30 square inches. 35 x 36 is 1050
If you got that for each tire, your vehicle weighs about 4,200 pounds.
If you inflate each tire more, you decrease the tire's foot print on the floor, so you take the higher psi times a smaller square inches and end up about the same. Lower the tire pressure to 30 psi you increase the tire on the floor, more square inches, same result in the end.
The air pressure holds your car up - not the tire. Pressure per square inch applied to an area is force - force supporting the weight of the car.