What is a Tire Pressure Monitoring System?
Tire pressure monitoring systems (TPMS) continuously check the pressure in a vehicle’s tires and report that information to the driver. Most of these systems measure pressure directly, but some infer pressure from observational factors such as tire rotation speed.
The first tire pressure monitoring systems appeared in the 1980s, but the technology didn’t become ubiquitous until much later. The technology’s adoption in the United States was fueled by the TREAD Act of 2000, which required all light motor vehicles in the United States to have some type of TPMS by 2007.
What is the tire pressure monitoring point?
Tire pressure often affects handling characteristics, which is the main rationale governments have used to legislate the use of these systems. Under-inflated tires can contribute to increased stopping distances, poor lateral stability, and other problems. If a tire is low enough in air, it can even overheat and fail catastrophically. When that happens at high speeds, the results can be devastating.
There is also an economic rationale behind tire pressure monitoring that should appeal to any car owner on a budget. Underinflation can have an adverse effect on gas mileage and tread wear, so keeping your tires properly inflated can save you money over time. If your tires are 10 percent underinflated, you’ll typically experience a 1 percent reduction in fuel efficiency. This may not sound like much, but it has a cumulative effect.
How does tire pressure monitoring work?
Most tire pressure monitoring systems use physical pressure sensors, battery-powered transmitters, and a central receiver unit. Each tire has its own pressure sensor, and battery-powered transmitters report individual pressures to the receiver. This information is processed and presented to the driver. In most cases, the system is designed to alert the driver if any of the tire pressures drop below a certain threshold.
The other method of monitoring tire pressure is sometimes called an indirect tire pressure monitoring system (iTPMS). These systems do not measure tire pressure directly, so they do not have battery-powered transmitters that require periodic replacement. In contrast, indirect measurement systems take into account factors such as the speed of rotation of the wheels. Because low pressure tires have smaller diameters than fully inflated tires, these systems may be able to infer when tire pressure needs to be adjusted.
What are the different types of systems?
The two main types of tire pressure monitoring technology are TPMS and iTPMS. However, there are also two main types of sensors used by tire pressure monitoring systems. The main type of TPMS uses sensors that are built into the valve stems of each tire. Each valve stem assembly has a built-in sensor, transmitter and battery. These components are hidden inside the wheels and can only be accessed by removing the tire. Most OEMs use this type of TPMS, but there are some drawbacks. Sensors are usually very expensive and tend to be somewhat fragile.
The other type of TPMS uses sensors that are built into the valve stem caps. Each lid contains a sensor, transmitter, and battery, just like the wheeled versions. However, this type can be installed without removing the tires. The main disadvantage is that the sensors are easily identifiable, which makes them vulnerable to theft. Both types of TPMS also have other advantages and disadvantages.
Can I get tire pressure monitoring on my vehicle?
If you buy a new car in the United States or the European Union, it already has some type of TPMS. All vehicles in the US have had them since 2007, and the EU instituted a mandate in 2012. If your vehicle is older than that, it may be possible to retrofit it with an aftermarket system.
Both valve stem and cap systems are available aftermarket, so you can choose from the systems you want. Valve stem sensors tend to be more expensive and require a visit to your mechanic for installation. Most shops charge a nominal fee to demount and mount the tires, but the actual installation of the sensors is typically free. This is due to the fact that installing a valve stem tire pressure sensor is no more complicated than installing a regular valve stem. If you’re already shopping for new tires, most shops will install sensors at that time for no additional labor cost.
If you don’t want to take your car to a tire shop or repair shop to have sensors installed, then you can purchase an aftermarket TPMS that uses cap sensors. These systems can be installed by simply replacing your existing valve stem caps with sensors from a TPMS kit. Most kits also have a 12-volt adapter that can be plugged into the cigarette lighter or accessory outlet.