Proper tire inflation

gitpicker2009 wrote:
Actually, at least in my opinion, if you want to run the tires at 80psi, you should fill to about 70 or 75 cold.
As the tire warms up, the actual pressure will increase.
Often explained as Boyles law, that's actually not correct. Boyles law is more concerned with pressure, though the two are related.
It's actually Charles law which lays out the relationship of temperature and volume, and it can be stated, simply, that most gasses have a direct relationhip between volume and temp.
Increasing temp results in an increase in volume.
If you set the pressure at 80psi, cold, then you can bet it's going to be closer to 90 at actual road temps.
I'd suggest slightly lower, and let them come up to the desired pressure/temp/volume during driving.

Just my humble opinion. My background was engineering, though I don't use it much anymore:)

anthony

For the other engineers out there:

Charles's law (also known as the law of volumes) is an experimental gas law which describes how gases tend to expand when heated. A modern statement of Charles's law is:
The volume of a given mass of an ideal gas is directly proportional to its temperature on the absolute temperature scale (in Kelvin) if pressure and the amount of gas remain constant; that is, the volume of the gas increases or decreases by the same factor as its temperature.
This law explains how a gas expands as the temperature increases; conversely, a decrease in temperature will lead to a decrease in volume. For comparing the same substance under two different sets of conditions, the as absolute temperature increases, the volume of the gas also increases in proportion. The law was named after scientist Jacques Charles, who formulated the original law in his unpublished work from the 1780s.