Rick has the best answer.

Each season, I line up all four tires that I took off in their positions, and I evaluate wear, looking for signs of over or under inflation, and wear pattern problems. I check them for nails, etc. and clean them for storage. I have looked at used snow tires and wheels that were put in plastic bags with salt on them, you would not believe some of the corrosion. Before I install the next season's tires, I line them up again and decide which tires should go on the front.

We run our wagons at half way between the half and full load pressures, maintaining the same ratio between front and rear. I think 34Front, 38Rear, I write the pressure on a small tag on the gas door next to Volvo's. We increase pressure to the full load numbers when carrying a load.

I used to run full load pressurs with our 7 series wagons, but the 850s show a tad of center wear if full load pressures are used all the tims.

If you use larger tires on your car than are shown on Volvo's tag, you should use lower pressures in your tires.
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96 855R, 95 855,854, 90 744 Ti - 340,000 Volvo miles put on 7 bricks