What is a tyre pressure monitoring system (TPMS)?

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

The tyre pressure monitoring system (TPMS) records the tyre 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 tyre pressure monitoring systems work?

Tyre pressure monitoring system means a system fitted on a vehicle which can evaluate the pressure of the tyres 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 gauge, 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 tyre under-inflation, a message can be sent to both the fleet manager and the driver of the vehicle so that the tyre can be inflated again.

Tyre 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 tyre temperature readings. A direct tyre pressure monitoring system collects tyre data and transmits it to a centralised control module to be analysed, interpreted and then directed to the driver’s dashboard when tyre pressure is lower than it should be.

The benefits of direct TPMS include:

Provides actual tyre pressure readings
Is more precise than indirect TPMS
Has a longer battery life (approximately a decade)
Reset is not necessary even after tyre 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 tyre 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 tyre pressure, it will roll at a different wheel speed than other tyres. 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 tyre 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 tyre, it may be inaccurate
Reset after inflating of each tyre and routine tyre rotation required
Potentially unreliable as tyres wear unevenly

Why do vehicles have tyre pressure monitoring systems?

As well as helping to ensure safe driving conditions, a TPMS offers predictive tyre management, so problems such as slow leak or abnormal tyre pressure are detected before they lead to costly repairs or downtime. When a tyre is running under inflation, it often consumes more fuel. Therefore keeping the tyre at its optimal pressure also helps save fuel and decrease tyre 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 tyre pressure monitoring systems (TPMS) have been mandatory on passenger cars in Europe since 2014.

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