A complete guide to tire pressure monitoring systems

What is a tire pressure monitoring system?

A tire pressure monitoring system is an electronic system that uses TPMS sensors to monitor the air pressure inside individual tires on different types of vehicles and trailers, ranging from long-haul trucks and passenger vehicles to trailers like dry vans, reefers, flatbeds, and tankers. A TPMS reports real-time tire-pressure information to the driver of the vehicle, via a gauge, pictogram display, or a low-pressure warning light. Some tire pressure monitoring systems can even automatically alert drivers via email or text alert. By calling attention to an over or under-inflated tire, the system can prompt the driver to inflate the tire to the proper level.

How does a tire pressure monitoring system work?

A TPMS includes sensors, typically within the tire, that send information to one or several modules in the vehicle or trailer. These modules can be pre-programmed with a designated tire pressure range so that you can be alerted if one or more of your tires goes out of that range. Some systems can also detect if the temperature is out of range or if there’s a leak or cross axle fault. There are two different types of tire pressure monitoring systems: 

1. Indirect TPMS: Indirect TPMS measure air pressure with software-based systems rather than physical sensors. While the software may leverage existing sensors—like wheel speed sensors or accelerometers—indirect TPMS monitors air pressure via the anti-lock braking system (ABS). The ABS provides tire pressure information by measuring the difference in the diameter of each tire.

2. Direct TPMS: Direct TPMS measures tire pressure using waterproof hardware sensors located in each tire (or on the valve stem). Each wheel includes a battery-driven pressure sensor which transfers pressure information to a central control unit. This unit then reports high or low tire pressure and temperature data to the asset's information system. Some sensors are mounted on the valve stem, other sensors are located in the wheel hub. When evaluating a TPMS tracking solution, consider one that allows for the flexibility to work with either sensor type.

Either option can be valuable when implemented as part of a broader tire management program. To learn which system is best for your fleet, you can read more about each system here.  

Why is a TPMS an important part of a tire management program?

While tire management can be overwhelming—it’s important to not overlook. Tire damage can contribute to major maintenance and safety issues across your vehicle and trailer fleet. In fact, tires are the third leading expense for fleets and if not properly monitored, can have large repercussions on your company’s bottom line. 

A TPMS is one great way to create a strong tire management program across your vehicles and trailers, but you should first carefully consider the best type of tires for your fleet. To inform this decision, fleets should evaluate their trucks, trailers, and routes to determine the type of climate and terrain they’ll be operating in—and then pick a tire accordingly. 

Once your fleet has selected appropriate tires, it’s important to properly maintain them. This means making sure your tires have the proper tread depth, temperature, and air pressure. While you can measure tire tread with a tread depth gauge or get a temperature reading with a tire temperature gauge, it’s best to use a TPMS to get an accurate air pressure reading of your tires.  

The best TPMS technology is able to notify you of each tire’s pressure in real time using tire pressure sensors that alert you as soon as tire over or under-inflation is detected. Many tire pressure management systems alert you with a warning light, while others include a gauge or LCD display that lets you know when the pressure is off the predetermined range. Some tire pressure monitoring systems can also alert you or your team via email or text message.

And while a tire management program can help alleviate tire damage and extend tire lifespan, it’s still a good idea to always carry a spare tire in case of an emergency. 

Five benefits of using a TPMS in your vehicle and trailer fleet

The benefits of a tire pressure monitoring system extend well beyond simply understanding your vehicle’s tire pressure levels in real time. If you manage a fleet, insight into each vehicle’s tire pressure can lead to major gains across your business. Read on to learn four ways you can leverage a TPMS to improve your fleet management: 

1. Improved fuel economy: Tire pressure can negatively impact your fuel efficiency because under-inflated tires have a greater resistance to rolling. In fact, according to the U.S. Department of Energy, you can boost your vehicle's mileage up to 3% by making sure your tires are inflated at the recommended air pressure. With a TPMS, you can be automatically alerted when air pressure drops lower than the recommended tire pressure so you can help your fleet stay as fuel efficient as possible.

2. Extended tire life: The average total cost of a flat tire for a fleet—when considering driver and vehicle downtime as well as the actual tire—is nearly $350 and over $400 for commercial trailer and tractors. If you have thousands of vehicles with multiple tires, this can quickly become a large cost. Under-inflated tires are a leading cause of tire failure and can contribute to other tire issues including cracking, component separation, or blowouts. In fact, a tire that is under-flated by just 20% can reduce tire lifespace by 30%. 

Over-inflated tires, on the other hand, can be more susceptible to enduring damage from debris or potholes. That’s why it’s important for your tires to have the recommended air pressure—too little or too much air will only increase the chances of an issue and decrease the lifespan of the tire. 

3. Improved safety: Over-inflated or under-inflated tires can lead to tread separation and tire failure—the cause of nearly 11,000 accidents annually according to the National Highway Traffic Safety Administration. Properly inflated tires add greater stability and more seamless braking, providing a safer experience for the driver and other vehicles on the road.

4. Environmental efficiency: According to the U.S. Department of Transportation, vehicles with under-inflated tires release more than 300 billion pounds of carbon monoxide in the United States each year. But by monitoring tire pressure across your vehicles, you can ensure tires are properly inflated so you can help reduce the emission of dangerous pollutants.  

5. Real-time visibility across vehicles and trailers: With a TPMS solution, drivers and the back office gain real-time visibility into tire and power status enabling fleets to proactively maintain their vehicles and trailers, stay in compliance, and improve operational efficiency.

How Samsara helps fleets improve safety and reduce maintenance costs

Maintaining proper tire pressure is essential for ensuring efficiency and minimize costs across your fleet. For trailers in particular, under-inflated tires force tractors to spend more fuel while hauling freight, increasing costs and reducing fuel efficiency. Additionally, incorrect tire pressure increases the risk of blowouts, leading to potential safety hazards and downtime. With each trailer having as many as eight tires, managing tire health across an entire fleet requires constant monitoring to prevent excessive wear and tear, ensure asset health, and drive operational efficiency.

Today, innovative technology like Samsara Smart Trailers make it possible for you to ensure the efficiency, safety, and compliance of your trailer operations with real-time insights and advanced trailer monitoring. With Smart Trailers, you can get ahead of tire pressure issues with full visibility into your fleet's trailer health. Samsara also has an expansive ecosystem of integrations that enables you to stay connected with your partners. With integration partners such as Continental TPMS, you can unlock data-driven insights that allow you to manage tire issues before they become over the road breakdowns.

To learn more about how you can take your trailer operations to the next level, check out Samsara’s Smart Trailers solution and chat with our team today.