[Jodele]

You are almost correct…

To get the best performance (stick), you want the most consistent contact patch, i.e. contact pressure. A tire that is consistently under inflated will ware out the outside edges of the tire tread (under the side walls) because the sidewalls are supporting the car. A tire that is consistently over inflated will ware out the center of the tire tread just like a balloon. Neither one of these conditions will give you optimum performance because one portion of the tire tread is loaded higher (and therefore over heating) than another and therefore that portion of the tire will lose traction before the other…I think that you can figure out that that is not optimum. The only way you can test to see if your tire is correctly inflated, is with a pyrometer (tire temperature gauge). Watch Formula 1 sometimes and you will see the suspension and tire engineers carrying one all the time. It is that important. The old ones used to use a needle to stick a probe down to the cord of the tire (through the tread of the tire). The new ones use infra red light to read the temperature. The light ones are also give you instantaneous readings.

If you have handling problems (over steer or under steer) and you need to fine tune your handling characteristics because you can not adjust your suspension properly (read this as a last resort), you can adjust your tire pressures to get the desired characteristics at the cost of tire ware and traction due to localized over heating of the tread.

If you don’t own a pyrometer, you’re not qualified to make haphazard tire inflation pressures like you did…