[RockyMtnRay]

Originally Posted by MikeD

Your understanding is correct. The reason I feel that this is useful are:

1. A leaking tire will probably continue to leak, so you will be notified.

2. You can easily check the tire pressure from the cab. This makes it very simple to do before leaving from a stop. The pressure should be at the cold point or higher and both tires shold be at approximately the same pressure. This makes it easy to check pressure during the trip and detect a problem before the alarm goes off.

3. If you look at the load inflation tables for the ST215/75R14 (my tires) at http://www.goodyear.com/rv/pdf/rv_inflation.pdf, you can see that the tire is down to a load of 1790 (loss of 80 lbs capacity) at 45 psi, and 1660 lbs (loss of 210 lbs) at 40 psi. I extrapolated that the load carrying capacity would still be about 1700lbs at 43 psi (I know it's not linear, but that's why I choose 43psi rather than 43.75psi). While not good for the tire, I assumed the tire would hold out for a while (at least until the lowering pressure triggered the alarm).

No perfect answers, but I believe that combining easy checking at each stop with the alarm function will give me a better chance at avoiding low pressure induced blow-outs.

MikeD

Only thing I'd add is that you don't have to wait until a stop to do a pressure check...you can check the tire pressures on trailer whenever you want to. I do it anytime I think something doesn't quite feel "right"...and sometimes if I just get bored. . As noted earlier, unless the tire has lost more than 12.5% of the baseline pressure, the "current" pressure shown won't be more than 5 minutes out of date. If any tire has dropped more than 12.5% below the baseline, the pressure shown is current to the nearest second of time.

But since the cold starting pressure is almost always going to be the lowest of the day, any pressure seen below that start pressure on a random check means a problem!