Underinflation can reduce tire life, tread life, and fuel economy, so monitoring your tire pressure by any means is like putting money in the bank.
By Bill Hendrix, F761S
February 2008
Loss of inflation pressure is a major factor in tire damage. Heat buildup from low pressure can easily exceed 200 degrees Fahrenheit, leading to devulcanization, ply separation, or a blowout. Sometimes an underinflated tire on the motorhome can be detected due to a possible change in handling characteristics, but this is extremely subjective. A towed vehicle is at greater risk, since you just can’t feel any difference from the coach driver’s seat. Tire monitors are becoming more popular, featuring technological advancements that have extended battery life and improved reliability of the products. Several years ago our coach picked up a small piece of metal in the right rear tag axle tire. The loss of tire pressure evidently was very slow, generating enough heat to cause a blowout. The separating tire tore off the coach mud flap and ripped out the brake line and air bag hose. Long story short “” $2,400 and four days later we were on our way again. All could have been prevented for a fraction of that amount with a tire monitoring device.
Here is a brief review of four tire monitor systems that currently are available for motorhomes and towed vehicles.
PressurePro sensors are valve-stem-mounted sensors/transmitters that electronically sample the pressure every 7 seconds and transmit data every 5 minutes. Their pressure range is 10 to 150 psi. If a 12.5 percent drop in baseline pressure is detected, a first-stage alert is immediately sent showing the pressure and the location of the tire. A 25 percent drop will trigger the second-stage, more urgent alert. Current production also includes a high-pressure alert feature. Sensor weight is approximately 2/3-ounce. Two different models are available: one for up to 16 tires and another for up to 34 tires. The system is active 24/7, and pressure may be checked at any time by scrolling through the tire locations with the dash display. Line-of-sight range is 100 feet, but a remote antenna and a rear-mounted signal repeater are offered as optional equipment for unique situations. During installation and setup, each sensor is programmed for a particular tire location, and the baseline pressure is automatically set when the sensor is screwed onto the valve stem. The sensors may be moved and reprogrammed when necessary. PressurePro tire pressure monitoring systems are produced by Advantage PressurePro and sold worldwide through distributors and dealers. A complete list of dealers is available at the company’s Web site. Advertised price for the monitor is $190, and the sensors are $50 each with a limited warranty of 12 months.
Advantage PressurePro LLC, 205 W. Wall St., Harrisonville, MO 64701; (800) 959-3505; www.advantagepressurepro.com.
SmarTire offers in-wheel sensors/transmitters that clamp to the drop portion of the wheel with a metal band. The sensors activate at speeds above 15 mph and report to a dash-mounted monitor. Data is transmitted to the monitor, where wheel position, pressure, and temperature are registered. Pressure and temperature will be monitored by the sensors every 12 seconds, and data is transmitted every 3 to 5 minutes. If a 3-pound change in pressure occurs, data will be transmitted immediately. There are three user-adjustable warnings: a pressure deviation alert will sound, giving an audible tone and a flashing light indicating the tire position if a tire deviates from its proper inflation; a critical low pressure alert will sound if the pressure falls further to a predetermined threshold below the cold inflation pressure level; and a high temperature alert will sound if a tire’s temperature rises above a preset threshold. You may scroll through the system to see tire pressure and temperature. To conserve battery life, data is transmitted only during travel.
SmarTire can accommodate vehicles of most any combination, up to a total of 20 wheels. It is necessary to dismount the tire in order to install the sensor on the wheel. Two or three undercarriage antennas are required to capture the RF signal from the sensors/transmitters. The third antenna may be necessary to accommodate a towed vehicle.
Two different types of sensors are available: one weighing 1.5 ounces for smaller tires with pressures up to 65 psi, and another weighing 1.89 ounces for larger tires with pressures up to 160 psi. Expected battery life is up to 5 years at 30,000 miles per year for the low-pressure sensor and 7 years at 50,000 miles per year for the high-pressure sensor. The receiver comes preconfigured with each sensor programmed for a designated wheel position. After installation of the wheel sensors, the receiver will be programmed for the various pressure and temperature alerts to meet a particular vehicle’s parameters. The product has a 24-month limited warranty, and service parts have a 12-month limited warranty. Contact a SmarTire dealer for price and installation cost.
SmarTire Systems Inc., Suite 150, 13151 Vanier Place, Richmond, BC, Canada V6V 2J1; (888) 982-3001; www.smartire.com.
Tire-SafeGuard offers five different configurations of sensors/transmitters for both inside the rim or valve-stem-mounted applications of up to 22 wheels. The most popular for RV use would be the stem-mounted, of which two styles are available. The Flow-Through style has a noteworthy feature of being able to inflate the tire without removing the sensor. The cap sensor is an excellent choice for towed vehicles. The sensors have a wide pressure range of up to 176 psi. The system’s advanced circuitry reportedly can extend battery life up to 7 years, and for most installations, a remote antenna is not needed. The sensors are preprogrammed when shipped, but can be reprogrammed by the user for any tire location. The pressure monitoring levels also can be adjusted by the user.
Two monitor styles are available. The standard monitor has a separate display unit and signal receiver. The dash monitor, which is mainly used for towed vehicles, requires no hookup, as it is powered by a rechargeable battery and can be mounted at any convenient location. Dual screens display the motorhome on one screen and the towed vehicle on another. The system monitors the tires continuously. Upon detection of an abnormal tire condition, the monitor shows a red light, activates an audible alert, and displays the pressure and location of the tire with low pressure. The advertised price is $195 for the monitor, $55 each for the flow-through sensors, and $50 each for the cap sensors. They have a two-year limited warranty.
HCI Corporation, 11245 E. 183rd St., Cerritos, CA 90703; (562) 926-7123; www.tiresafeguard.com.
Tire Sentry uses valve-stem-mounted pressure sensors/transmitters that check the pressure mechanically and use battery power only to transmit an alert to the dash display when an air pressure loss of 10 percent or more is detected. This allows the tires to be monitored 24/7 without battery drain. The sensors weigh less than one ounce and are preprogrammed for the vehicle’s wheel configuration and pressure requirements. Sensor pressure range is 18 to 130 psi for combinations of up to 18 wheels. In most cases, a remote antenna is not needed, because of the excellent range of the sensor/transmitter and the simplicity of the data. Tire pressure is not shown on the dash display “” just an alert for low pressure for the specific tire location. The 2-inch-round Tire Sentry display may be flush-mounted in the instrument panel or pedestal-mounted to any convenient location. Battery life of two to three years may be expected, and the batteries are replaceable with two standard watch-type batteries. The company also has introduced models TMS-04RC and TMS-06RC that are said to be the first totally wireless systems that plug directly into a DC accessory socket and can monitor a towed vehicle or trailer. In addition, when the plug-in receiver/display module is transferred from the motorhome to the towed vehicle, that vehicle’s tires can be monitored when not being towed. Tire Sentry comes with a 3-year limited warranty; systems start at $345.
Fleet Specialties Co., 31328 Via Colinas, Suite 104, Westlake Village, CA 91362; (818) 889-1716; www.tiresentry.com.