What is TPMS?
Tire pressure monitoring systems ("TPMS") are integrated assemblies that include sensors in the tire stems, and they exist for the purpose of warning a driver when the air pressure in any of their tires has dropped to an unsafe level. To do this, pressure detectors are fitted on the part of the stem that sits inside the tire. Those pressure detectors each have their own battery and transmitter which relay information to the car's main computer. A normal-looking stem protrudes outside the tire for the purposes of adding air, and looks indistinguishable from traditional valve stems that don't have pressure sensors.
As far back as 1970, the U.S. National Highway Traffic Safety Administration (NHTSA) looked into the benefits of low tire pressure warning equipment. However, technology did not exist to make such devices practical or affordable. Later in the 1970s, an Indiana State University study suggested that under-inflated tires were the cause of 1.5 % of all motor vehicle crashes, because tires low on pressure hamper handling and braking on dry and wet roads. An independent study by Goodyear yielded a similar conclusion.
After the second major fuel crisis of 1979, NHTSA again considered mandating low-pressure warning equipment as a means to reduce fuel consumption by the general public. At the time, vehicles with radial tires that were properly inflated achieved mileage gains of 3-4 % compared to those with tires underinflated by 10 psi. By the early 1980s, tire pressure sensor technology had advanced somewhat, but equipment was still not reliable or accurate enough for prime time. A cost increase of $200 per vehicle during the recession of the time was the final nail in the coffin of TPMS - at least temporarily.
After an initial appearance on the low-production and very-expensive 1987-89 Porsche 959 supercar, tire pressure monitoring systems made a mainstream debut on all 1991 Chevrolet Corvettes. Because the Corvettes were equipped with run-flat tires that remained drivable for a certain number of miles after losing all air pressure, TPMS was required to warn drivers when there was a deflation problem. Because sidewalls of run-flat tires are designed to maintain integrity for 50-100 miles, a driver could be unaware of the situation without a warning light - until tires were driven past their limitations. After that, tire pressure sensors slowly began to increase in popularity on more expensive performance cars.
Perhaps the single biggest factor that brought attention to the subject of tire pressures and safety was a large number of rollover crashes by 1990s Ford Explorer SUVs - all of which were equipped with Firestone brand tires. Ford internal documents later revealed that when the first-generation 1991 Explorer was being developed, engineers noticed the vehicle had a propensity to roll over in emergency maneuvers. Changes to suspension design and axle width were recommended to solve the problem, but were not taken because of high costs of redesigning things at that late stage - changes that would have also delayed model introduction by at least a year.
Ford's response was to specify a lower-than-average tire pressure setting of 26 psi. While this reduced vehicle instability at critical moments, it also caused separate problems from heat buildup due to increased tire rolling resistance. This heat buildup led to tire failures at speed when the tire tread separated and literally peeled away from the rest of the tire. Needless to say, these tire deflations ended up causing rollovers - the exact problem Ford was trying to avoid.
It's been estimated that over 3,000 injuries and 250 deaths resulted from Explorer-Firestone related crashes. During U.S. Judiciary investigations in 2000, Firestone cited improper guidelines by Ford as the root of the problem while Ford blamed tire design flaws that could have been corrected by Firestone. While tire recalls and wrongful death lawsuits that resulted have faded in the rearview mirror of history, awareness of the relationship between proper tire inflation and safety did not.
The U.S. Congress passed the Tire Recall Enhancement, Accountability, and Documentation (TREAD) Act of 2000. Among other things, that act mandated that all passenger vehicles weighing under 10,000 pounds sold in the U.S. as of September 1, 2007 be equipped with a Tire Pressure Monitoring System that warns drivers if any of the tires on the vehicle are underinflated by 25% or more (a phase-in began in 2005). More specifically, it said the TPMS must also be operative whenever the ignition is switched on and alert the driver if a malfunction in the system occurs.
For "bulb check" purposes, the low pressure warning light must display on the instrument panel for 1-2 seconds after startup. Vehicle owner manuals must warn owners about the dangers of replacement tires that could potentially be incompatible because of different pressure specifications. So, while Tire Pressure Monitoring Systems had been around as optional equipment for years, any 2008 or later model year vehicle in the U.S. is equipped with them as standard equipment.
The actual sensors in the tires wear out over time as high levels of vibration and pressure take their toll and transmitter batteries reach the end of their usable lifespan. When this happens, sensors no longer transmit a clear, steady signal. If you've got a constant "no display/low pressure/error message" from your Tire Pressure Monitoring System that can't be cleared out or turned off by properly inflating the tires, then you likely have one or more dead tire sensors that need to be replaced.
If your vehicle is already equipped with TMPS, we have replacement sensors from Oro-Tek, Dorman, Standard, Auto 7, Denso, Omix-Ada, and Crown. These are vehicle-specific, and are designed to adapt to existing software your car or truck has in order to function the same way as original equipment. Dorman sensors require the Dorman Multi-Fit TPMS Programmer for vehicle synch up.
If your vehicle was not originally equipped with a TPMS system, we offer a cost-effective kit that lets you transmit, receive, and display data about all four of your vehicle's tires. The Omega R&D Excalibur Tire Pressure Monitoring System is a universal-fit kit that works with any car or truck. Instead of sensors that mount inside your tires, Omega R&D sensors screw onto the outside of your valve stems, in place of your valve stem caps. Once in place, they continually measure tire pressure using valve stem pins, and a digital monitor that plugs into your vehicle's cigarette lighter adapter provides a clear reading of each of the tires. Alarms will sound if fast or slow pressure drops are detected. This system is also an option for keeping an eye on tire pressures if your original system is no longer functioning.
How Effective Are Tire Pressure Monitoring Systems?
How effective are tire pressure monitoring systems? In a 2012 study, NHTSA released the results of a detailed research study that showed TPMS systems reduced the likelihood of severely underinflated tires by 55%. With the components we offer, there's no reason not to restore lost TPMS function or add it to an older vehicle. We trust that you enjoyed reading about the history of how Tire Pressure Monitoring Systems evolved, and we urge you to contact us seven days a week with any questions you may have.