Quote:
Originally Posted by lwmcguire
The real world way to tell if you are underinflated is to monitor the tire temperature. If you have tires you can't hold you hand on when driving in hot weather you are damaging your tires.
We ran trucks and trailer for over 50 years commercially and not one time did we ever let air out of tires when running back empty. Same goes for commercial rigs now. If you are going to error then error on the higher side of inflation, not the lower.
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I'm not feeling good about this advice. If the tire is inflated 20% or more under the recommended inflation pressure, it could result in rapid deflation without the chance to put your hand on the tires. I suppose you could watch temps on your TPMS, but I am sure that is not what a tire designer intended. Tire temperature is important when the temperature gets high enough for reversion of the rubber, but generally irreversible radial casing fatigue has already happened by that point. That will lead to the rapid deflation I referenced. In the industry, this damage is referred to as a "zipper" failure.
I do agree with the post above about changing pressures. Loads don't generally change enough on RVs to monkey with pressures with empty/full conditions, but I don't think that was asked about here. Erring on the high side is sound advice to a point. Running 120 psi when the recommended is 82 psi is akin to running 47 psi in your car when 32 psi is recommended. Probably won't have a tire failure, but the ride quality and the wear patterns on the tires will be unacceptable.
Most everyone has given good advice on this post. Weigh the RV to get the proper inflation. The procedure for setting pressure is a bit different for a F/R weigh and a four corner weigh.
With a F/R weigh, you take the front weight and divide it by 2 to get a corner weight. Look up your pressure and then add 5 psi or 5%, whichever is greater to determine front cold tire pressures. Do the same for the rear, but remember to look on the "dual" row on the chart.
For a four corner weigh, you look at the highest of the LF and RF and set your front pressure based on that weight. You do the same for the rear.
As stated, without weighing the vehicle, inflate to the placard pressure. This pressure is generally based upon the max axle rating on the RV.
I often tell people that RV owners know more about tires than any other tire customer.
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