Correct Tire Pressure

kohldad wrote:
I'm not an expert by any means, but I am a farm boy with an engineering degree.

Advice 1 and 2 are both safe ways to operate. Tire pressure is always performed when cold (less than 1 mile driving and without the sun shining on them). The sun heating up a tire on your driveway can effect the pressure by more than 5 psi.

My advice is based on these two facts:
1) Under inflated tires don't last long and usually end their life in a catastrophic event.
2) Higher than necessary pressure, but not exceeding max pressure, will more than likely last until they wear out. However, they may wear out in the center first.

For these reason for SRW, I recommend max pressure. Worst case is the ride may be a bit harder than necessary and the center may wear out faster. An advantage is the sidewalls will have less flex which reduces sway and increases control.

If you are worried about the harsh ride, reduce pressure when not carrying the weight. However, I leave my tires at max pressure (80 psi) 99% of the time. I only carry stuff about 1/2 my miles, but don't really know until a few hours before. I'm on my fourth set of tires and they have all worn down evenly.

I'm no expert either but this is the philosophy I follow. A tire under inflated for the load is unsafe. A tire inflated to max cold pressure is safe as long as it's under the max rated load, but may have a harsh ride and wear unevenly. Technically lanerd's answer is the most correct regarding ride quality, tread wear and safety. But it is also complex. If your primary concern is safety and can live with a little uneven tread wear and a stiffer ride, I prefer the simpler solution. Also, keeping the tires at or near max cold pressure minimizes rolling resistance and increases fuel mileage.

My $0.02
Dan