Maintaining air pressure in your tires
I've had my RV for less than a year and I'm religious in checking it's tire pressure. I had an inside rear dual that always seemed to loose a little tire pressure, so I checked pressure often. I thoug...
Forum Discussion
btim wrote:
I have TPMS on my Class C E450. I keep the tires inflated to mfr recommended psi. I also keep the TPMS display on while driving so I can monitor the pressures. I get a bit alarmed watching the pressures rise as I travel, especially in hot weather. Is it normal to see the pressures go from 80psi to 90psi or higher? I do not want a blowout! How accurate is the Ford TPMS system? It is usually within 1-2 PSI of my Slime tire pressure gage. But how accurate is that thing?
Yes, it's normal for the pressure to go up that much with temperature while driving. That's why the pressures are stated as cold pressures. The tires and wheels are designed to withstand the additional pressure encountered while in use with a sufficient margin for safety (assuming you're not doing silly things like greatly exceeding the speed or weight ratings of the tires--particularly both at the same time).
If your slime guage is a digital gauge, it's almost certainly dead nuts accurate, or very close to that. If it's an analog/mechanical one, it may be a little less accurate, but the fact that it correlates well with the TPMS readings strongly suggests that both are plenty accurate for any practical use. Being one or two psi off isn't going to cause any trouble. Perhaps the place where precision matters the most is in matching pressures on the two tires on one side of a dually axle, and there it's matching closely to each other that demands the closest precision, rather than matching exactly the specification in absolute terms.
None of that, of course, is license to drive with significantly overinflated or underinflated tires, which is decidedly not safe.
