Tire psi

Tireman9 wrote:

goufgators wrote:
As most (if not all) of you know, psi increases as tires warm up due to driving. My experience, here in Fl. where air and road temperatures get ungodly hot, is that it is not unusual for tires to gain 10 or more psi within just a few miles of driving. That increase in pressure begins to make ride and handling less pleasant! Question: if I should be running 90 psi, is there any reason why I cannot start with a cold psi pressure of 5 pounds less than 90 knowing that within about 5 miles I'll be right back up to or beyond the required 90 psi? Thanks / Larry

A gain of 10 psi in just a few miles gives a hint on a couple problems. Pressure should only increase by about 2% for each 10F increase so a 50 degree rise should take more like 30 minutes or more at full highway speed
1. The tires do not have the proper cold inflation so are over deflecting when you drive.
2. The tires were inflated with "wet" air. This is more likely a problem in areas of high humidity when tire shop or service stations do not do proper maintenance and drain the water out of their compressor.

Have you confirmed your tire loads with a quick check to a CAT scale? You just take your individual tire loads and add them up to get the expected reading on a CAT or similar truck platform scale.

To check for excess moisture simply pull a tire valve core and let air out for about 5 seconds. If you see any water droplets come out you need to have the tire air purged by a competent tire shop.
WARNING only do this at a location where you have access to air sufficient to re-inflate your tires.

From OP: Tireman, you're right! I misstated when I indicated an increase of 10 psi within a few miles. The increase of 10 or more psi is after driving a considerable distance on a hot road. But, after driving only a few miles, the psi does begin to increase per my TP monitoring system.