Over the past year, I have been involved in beta testing an active tire pressure monitoring system that is simple to install , very accurate and is now commercially available. The sensors simply replace your existing valve stem covers. Each sensor weights about 1/2oz so it does not effect tire balance in most cases. The sensors are a cylindrical design about 1" tall X 1" in diameter. The system will monitor 6 tires on the trailer and 10 tires on the tow vehicle. The pressure set point is established when you screw the sensor onto the valve stem (ie the existing pressure becomes the setpoint for alarming, but the sensor ALWAYS sends the ACTUAL pressure). If you realize that a tire is low once you have attached the sensor, simple air up the tire and reattach the sensor which will set the new pressure as the setpoint. Each sensor sends a digitally encoded FM signal (better reception and range) to the monitor every 5 minutes if things are normal as well as each time the tires have been sitting for more than 15 minutes and then start rolling. You can also manually trigger a reading by holding a magnet near the sensor for a few seconds. If a tire's pressure drops 12.5% below the setpoint, the sensor sends a reading and the monitor warns you with a simple beep, the actual pressure and a flashing indicator at the tire location in question. If the pressure drops 25%, again the sensor send a reading and the system goes into alarm mode, which is a constant beeping, the actual pressure and the same flashing location indicator. At any time, you can press a button and cycle thru the current tire pressures. The manufacturer (www.advantagepressurepro.com
) states that the reception range is in the 100' catagory, so even with a crewcab 1ton pickup or a Burb/Excursion and a 34', the A/S tires would still well within range.
My Bambi tires run a recommended 65PSI cold and at highway speeds have increased to about 72-73PSI. My LT truck tires run 50PSI (when I tow) and increase into the mid 50s. Even with diligent checking before we leaving and at rest stops, there is always the potential for leaks as we travel and catching that situation in time has always been a matter of luck. With active monitoring, checking the pressure on all the tires is a simple matter of pressing a button.