JPedro wrote:
Back to the question..... I keep my rear tires at the door sticker recommended 70psi, but within a half hour of driving with my overloaded TC the tire sensors show 80psi. Seems about right, but I wouldn't want to start out at 80 and go to 90. I'm wondering if folks with 19.5's see their pressure go from 110 to 120psi?
This pressure increase is normal. The tyre inflation/load tables specify that initial pressure must be done with cold (ie ambient temperature) tyres and the running pressure will be correct once the tyres warm up. My bigrig pressures go up by far more than 10psi, especially on a hot day and especially on the side facing the sun.
In some cases - because excessive tyre flex of underinflated tyres generates more heat which increases the hot running pressure, increasing the cold pressure to the correct value might actually result in a lower hot running pressure. This fact is used by some to determine what the correct pressure should be. Small sedan tyres - 4psi increase. Less means too hard, more means too soft. Larger 4x4 tyres - 6 psi increase and so on. Not an exact science but apparently works for some.
BTW Rated rim pressure may be a limiting factor when high load rated tyres are fitted in an effort to handle overloading.
