What is a tire pressure monitoring system (TPMS)?

Tire pressure monitoring systems can be a crucial part of extending your tires' lifetimes. They help you avoid vehicle downtime by keeping the correct tire pressure and keeping the vehicle safe on the road. They are designed to monitor tire air pressure or temperature and warn you when something abnormal is detected, such as under-inflation.

The tire pressure monitoring system (TPMS) records the tire pressure in real-time to help drivers and fleet managers keep an active eye on the condition of their vehicles and make sure they are operating a safe and well-maintained vehicle. This article will discuss how TPMS works, why vehicles have it and the benefits of TPMS.

How do tire pressure monitoring systems work?

Tire pressure monitoring system means a system fitted on a vehicle which can evaluate the pressure of the tires or the variation of pressure over time and transmit corresponding information to the user while the vehicle is running.

A TPMS reports air pressure information to drivers either through a gage, a pictogram display or a simple low-pressure warning light on the dashboard.

When TPMS is used together with an online fleet management software. The measured pressure data of each wheel is sent to an online cloud administered by the fleet manager. In case of tire under-inflation, a message can be sent to both the fleet manager and the driver of the vehicle so that the tire can be inflated again.

Tire pressure monitoring systems can be split into two categories: direct TPMS and indirect TPMS.

Direct TPMS

Direct TPMS monitors air pressure with hardware sensors, usually mounted in the wheel. It can even monitor tire temperature readings. A direct tire pressure monitoring system collects tire data and transmits it to a centralized control module to be analyzed, interpreted and then directed to the driver's dashboard when tire pressure is lower than it should be.

The benefits of direct TPMS include:

Provides actual tire pressure readings
Is more precise than indirect TPMS
Has a longer battery life (approximately a decade)
Reset is not necessary even after tire rotation and inflation

Disadvantages of direct TPMS:

More expensive than indirect TPMS
If the battery is drained, the entire sensor must be replaced
Sensors may be damaged during mounting/demounting

Indirect TPMS

An indirect tire pressure monitoring system does not measure physical pressure but uses software-based systems to evaluate and combine existing sensor signals such as the wheel speed, anti-lock braking system, accelerometers and driveline data. When the vehicle has low tire pressure, it will roll at a different wheel speed than other tires. This will be detected by the software system and trigger the indicator light on the dashboard.

The benefits of indirect TPMS include:

The wheel revolution rate measures tire pressure
Relatively inexpensive compared to direct TPMS
Requires less maintenance over the years than direct TPMS

Disadvantages of indirect TPMS:

When purchasing a bigger or smaller tire, it may be inaccurate
Reset after inflating of each tire and routine tire rotation required
Potentially unreliable as tires wear unevenly

Why do vehicles have tire pressure monitoring systems?

As well as helping to ensure safe driving conditions, a TPMS offers predictive tire management, so problems such as slow leak or abnormal tire pressure are detected before they lead to costly repairs or downtime. When a tire is running under inflation, it often consumes more fuel. Therefore keeping the tire at its optimal pressure also helps save fuel and decrease tire wear.

This, in turn, helps you to cut running costs, improve road safety and reduce your impact on the environment. And, with less chance of breakdowns, there’s less chance of service disruption.

It should also be noted that tire pressure monitoring systems (TPMS) have been mandatory on passenger cars in Europe since 2014.

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