SAN ANTONIO, TX. Pressure Systems International (PSI) plans to offer two new enhancements to its automatic tire inflation system available in September. One is specifically designed for steer axles on a Class 8 tractor, while the other is a new wheel end heat sensor package to warn of an impending wheel bearing failure.

PSI builds its system with ArvinMeritor, calling it the Meritor Tire Inflation System (MTIS) by PSI.

“The steer axle tires are the most critical on a tractor as there are only two of them, as opposed to the four tires found on the drive and trailer axles, and they typically get the most wear,” explained Frank Sonzala, PSI’s executive vp, here at a special fleet technology preview hosted by the company.

PSI has been testing its steer axle tire inflation configuration for three years now, said Sonzala, including 500,000 miles of testing on a truck running from Prudhoe Bay, AK, to Seattle, WA and back. He believes including steer tires within PSI’s automatic tire inflation product will reduce tire wear, eliminate the need for drivers to hand-check tire pressure on their vehicles, and boost fuel economy.

The wheel end heat sensor package is a different modification – it’s an inexpensive pneumatic heat sensor designed to give fleets and drivers the ability to take action before a catastrophic wheel end failure occurs, said Sonzala.

A special heat-sensitive “utectic” material is screwed into a small area right under the wheel bearing. It’s designed to melt at 281° F, which is the heat threshold for a wheel end failure, said Sonzala.

Once it melts, it activates a blue light on the dashboard and causes a wailing sound to come from the wheel end to signal the driver to stop immediately, he said. The sound and light can only be deactivated if the wheel end is removed and the material replaced.

“It’s all about giving drivers and fleets a chance to take action before a wheel end fails – potentially causing a wheel end to separate and come off the truck while it’s in motion,” said Sonzala. “It will help fleets avoid such a disastrous situation.”