TPMS - What Is It and How Does It Help Me?

Tyre pressure monitoring systems, or TPMS for short, are now a mainstay for all European made passenger vehicles. As of 2012, all manufactured passenger vehicles must be equipped with either a direct or indirect TPMS system (more on this down below!). In addition, during the MOT, the tester should encounter no errors with this system. These errors manifest themselves via a dashboard warning which can clearly been seen by the driver.

These little devices track the pressures in the tyre and relay the information to the user in the cabin of the car. Extremely helpful if you encounter a slow or fast puncture whilst driving!

From the above text, what are the differences between the two types of systems and what's mine?

Sadly, with each and every new car model that appears on our road, knowing who has which system becomes more and more cloudy and there is no definitive way to tell! Whilst in-direct TPMS systems are generally rubber valves and metal valves correspond to direct systems, the two can cross over. Sadly, it's a little bit of a minefield!

Indirect systems use the ABS ring on the wheel hub to measure the rolling resistance of the tyre. Using a complex system of calculations, the car's computer can then determine what the pressure is. If this resistance drops then this is immediately alerted to the cars display to warn the driver. The main advantage to having this system is that it is cheaper and easier to service. However, the big drawback is that the car won't tell you which tyre has been affected due to these sensors going to one 'central hub' that then relays the information to the car dashboard. If the pressure drops, the driver is warned of low pressure. But, the system does not indicate which one is down.

Direct systems are sensors found in the valve of the wheel hence it being metal! While being powered by a battery, these systems continually monitor the air pressure inside the tyre and alert the driver to any issues or loss of pressure. The main advantage to using these over the in-direct system is that when a tyre is low, the on-board display will tell you which tyre is affected. In addition, the on screen display can show the real time pressures of the tyres and in some occasions, also their temperatures!

However, there are a couple of big draw-backs. These sensors have a battery life. After about five to six years, the sensors need to be replaced. But, as the battery is part of the sensor unit, the whole unit needs to be replaced. This, in turn, comes at a price. Often these systems are two to three times more expensive compared to the indirect systems and thus can be found more commonly on the premium brand vehicles.

If you were looking at servicing you TPMS system, have a puncture or just need some advice, why not give us a call on 0333 444 5454 or send an email to info@hometyre.co.uk where one of our friendly members of staff can help!