LOUISVILLE -- Bendix engineers are warning truck owners that if they aren't careful about the choice of replacement friction new trucks designed to meet the latest stopping distance requirements, they could negate the improved stopping distance that was designed into the trucks.

The company studied the most popular friction materials, representing about 70% of aftermarket friction sold, and said trucks equipped with those materials were seeing as much as 96-foot-longer stops or five car lengths.

"We didn't just decide to build bigger brakes," explained Fred Andersky, director of government affairs, during a press event at the Mid-America Trucking Show Wednesday morning. "We put together a system with a larger drum, improved friction and reinforced shoes.

"NHTSA is really only regulating the new vehicles. It's up to the fleet, it's up to the technician, to make sure that reduced stopping distance continues," he says. "Using the parts and friction they used to use isn't going to do it. It's important to think about these new brakes as a system."

The stopping distance regulations have driven the greatest changes in foundation brakes, especially drum brakes, since the move to non-asbestos brake linikngs about 30 years ago, said Gary Ganaway, director of arketing and global customer soltuison for Bendix Spicer Foundation Brake.

"On the surface the brakes will look very much as they always have, but the technology has changed drastically," Ganaway says.

One of the engineering changes made was the ability to reduce the amount of brake fade, Ganaway said. "Not nearly where we are with air disc brakes, but beginning to close the gap."

Bendix says part of the key is what it's calling high-performance brake friction, which is made from a combination of organic and semi-metallic materials. The latter help decrease brake fade.

"I spend a lot of time talking to fleets about this, and it's remarkable how safety conscious the fleets are," Ganaway says. "But we also find they simply don't understand the tradeoffs."

While aftermarket friction suppliers say they offer products just as good as the OE brake linings, Ganaway says that's generally not the case with these new high-performance materials.

Leading to confusion in the marketplace is that aftermarket friction suppliers may market their products as meeting dynamometer testing requirements that are no longer part of the federal regulations. The government has moved to the stopping distance performance requirement. So it's important to talk to your friction supplier about whether your brake linings are designed to meet these new requirements.