The best way to determine the proper tire pressure is to set the pressure at the book reccomendations. Then take it out and ride it at highway speeds for at least 15 minutes. Now pull over and check the tire pressure. The pressure should increase about 10% over the cold pressure.
If you start out say 28 rear 23 front, after the 15 minutes they should increase to 30.8 rear and 25.3 front. With most pressure gauges getting that precise will be hard, a digital gauge will be easier to use.If the increase in pressure is less than 10% your cold pressure is too high. If the change is more than 10% the cold pressure is to low.
As the tire rolls the sidewalls flex, This flex creates heat which increases the pressure. To operate as designed the sidewalls must flex a certain amount. This amount of sidewall flex creates the 10% increase in pressure. A soft tire flexs to much, creates to much heat, too much pressure. To hard a tire, not enough flex, no heat, no increase in pressure.
When you add a passenger or carry a load, then reset the pressure the same way. The heavier the load the higher your pressure needs to be.
This works well with any tire, car, pickup, any tire that goes faster than about ten MPH.
Leo
