According to Bendix, a tyre that is under-inflated by as little as 10% can result in a 1.5% drop in fuel economy, which may increase fuel spending by up to US$1,000 per year for a single truck. Under-inflation by 20% results in a 30% reduction in tyre life.  In this interview, Matthew Beecham talked with Jon Intagliata, product manager for tyre pressure monitoring systems at Bendix Commercial Vehicle Systems.

Under-inflated truck tyres are estimated to cause nine out of ten tyre failures as well as faster tyre wear and reduced fuel economy. Could you explain your SmarTire product, i.e. how it works and its unique benefits?

SmarTire TPMS by Bendix CVS uses sensors mounted on the rim, inside the tyre that measure both pressure and temperature, allowing the system to provide temperature compensated warning information. With this information, we are able to provide accurate warnings of a potential tyre problem. One of the key features of the Bendix system is that it uses accurate pressure and temperature to calculate a Deviation Value that is displayed along with the pressure and temperature. This Deviation Value is calculated by looking at the tyre actual pressure, and comparing it with the “proper” pressure for that tyre at its current temperature. 

As contained air is heated, the pressure will increase. Thus, as the tyre heats up, the pressure increases. The SmartTire TPMS system takes this increase into account when providing warnings. For example, a tyre with a Cold Inflation of 100PSI, when at operating temperature, shows around a 15PSI increase in pressure. Many systems ignore this increase and if they provide a warning when the tyre is 10% low, will not warn until the tyre reaches 90PSI. Our system will take this increase into account and warn the driver when the pressure drops to 105PSI, 15PSI earlier.

Additionally, SmarTire TPMS will not provide false warnings due to changes in ambient temperature. For instance on a cold day, the pressure of a tyre set to 100PSI could drop to 88 PSI and cause may system to issue and alert. When the tyre heats up, that alert will disappear, causing confusion with the driver. Our system will look at the temperature and not issue a warning because at that temperature, the pressure is correct. Finally, if a driver is stopped for fuel and has a low tyre, the Deviation Value eliminates the guesswork from deciding how much pressure should be added to the tyre, just look at that value and add the appropriate amount of air.

I guess all types of fleets can benefit from using your SmarTire yet is it particularly beneficial for fleets operating high-cost trailers, high-value cargo, refurbished trailers, and wide-base single tyres?

The SmarTire TPMS system benefits any fleet who wants to increase fuel economy and improve tyre life. This is especially important for fleets with high-cost trailers, ones that run super-singles or haul high-value cargo. SmarTire TPMS provides and peace of mind, additional protection and prevents potential tyre failures that could cause damage. Additionally, SmarTire provides a temperature warning so if there is a potential bearing failure or dragging brake, the system will warn the driver if there is excessive heat build-up that could lead to a fire in the wheel-end. For any fleet operating wide-base single tyres, the SmarTire TPMS system is invaluable. Preventing one tyre failure will more than pay for the cost of the system. In many cases, if a wide based single tyre fails, it not only destroys the tyre, but the rim as well.

Since legislation on TPMS was introduced in North America, in what ways have those regulations changed how fleet operators think about TPMS and how they select them?

The TREAD Act does not require TPMS for vehicle with a GVWR of greater than 10,000 lbs. We do not expect to see TPMS requirements extended to light-duty (above 10,000 pounds) or medium-duty commercial trucks. The cost saving aspects of TPMS, we believe, will drive the adoption in NA.

As we understand it, TPMS technology is evolving to the point where one scenario could be this: As soon as the TPMS tells you that your tyre needs servicing, the nearest licensed service station will be automatically alerted through your car’s GPS, giving you directions to a site where qualified personnel will be awaiting your arrival. Is this correct? What could tomorrow’s commercial vehicle TPMS offer?

Yes, this is all possible. Bendix has integrated SmarTire TPMS reporting into our back office driver reporting system called SafetyDirect. A fleet manager will be able to look at his fleet or individual drivers to get real time status information for each truck/tyre operating in their fleet. They will get email alerts for user defined faults and can contact the driver to direct them on how they would like to handle the fault.


Bendix Commercial Vehicle Systems, a member of the Knorr-Bremse Group, develops and supplies active safety technologies, energy management solutions, and air brake charging and control systems and components under the Bendix brand name for medium- and heavy-duty trucks, tractors, trailers, buses, and other commercial vehicles throughout North America. Headquartered in Elyria, Ohio, Bendix Commercial Vehicle Systems operates manufacturing plants in Acuña, Mexico; Bowling Green, Ky.; and Huntington, Ind.

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