Direct TPMS Versus Indirect TPMS

TPMS (Tyre Pressure Monitoring System) is a well-known safety feature and has the following benefits:

• Lower accident rates due to optimised handling and braking capabilities 
• Less CO₂ emissions
• Longer tyre lifespan
• Reduced fuel costs

TPMS is beneficial on both personal and societal levels by ensuring that tyres are properly inflated. No wonder it is already a mandated safety measure in the EU, US and China. There are two types of TPMS: direct TPMS (dTPMS) and indirect TPMS and they function in different ways. Knowing those differences will help you understand and advise the best solution for your customers. 

What is the Difference Between Direct and Indirect TPMS?

Direct TPMS (dTPMS) gathers accurate pressure data directly from the tyre valve via four dedicated pressure sensors that are attached to the valve, transmitting pressure readings in real-time. Indirect TPMS, on the other hand, uses the ABS (anti-lock braking system) to approximate tyre pressure, and motorists must drive a substantial distance before an alert can be generated.

Which System Works the Best?

As the debate over direct and indirect TPMS technologies continues globally among regulatory, consumer and industry groups, one thing is clear; consumers, when given the choice, express a preference for the direct TPMS scenario, that uses pressure sensors installed in each tyre, such as Schrader’s EZ-sensor^® family of products. Research conducted by fast.MAP on behalf of Schrader has revealed that 69% of drivers do not wish to undertake the responsibility of manually resetting an indirect TPMS system. Because of the absence of pressure sensors, a vehicle equipped with indirect TPMS requires the device to be recalibrated by the driver after tyre pressure is modified or a tyre is changed. This puts a level of control in the hands of the driver, something that is not the case with other critical safety functions in the vehicle such as airbags.

What Makes Indirect TPMS Impractical? 

For indirect TPMS to work effectively, all four tyres must be inflated to the correct recommended pressure and be under optimum conditions. This seems like a defeating proposition for consumers because the very reason they see the value in TPMS is to help them maintain the optimal tyre pressure. Similarly, indirect technology requires the consumer to install specific tyres when replacing the originals in order to operate properly with the system. Lastly, if all four tyres are similarly low in tyre pressure from neglect (a common problem) or other reasons, an indirect system will not trigger a warning alarm. When all four tyres are low, the tyres wear quicker on the edges and the car is unsafe and unstable to drive, has less traction on wet roads, takes longer to stop, and uses more fuel. 

In conclusion, with so many variables about indirect TPMS that leave your brand vulnerable to dissatisfaction and warranty issues, direct TPMS just makes sense– for you and your customers.

Which system are you more familiar with? Which one would you recommend to your customers?