Bendix said its ADB 225 air disc brake system weighs 30% less than comparable European models. Cutting weight out of air disc brakes is critical to getting U.S. fleets to accept them, said Ron Bailey, Bendix's technical sales manager.
"Today's air disc brakes are improved over earlier systems where weight, cost, and balance issues prohibited them from being a compelling option in the past," he said. "Fleets in the U.S. are very weight conscious and that's been one of the reasons why there's been resistance to air disc brakes in the past."
Bailey added that the key to selling air disc brakes will be their improved stopping capability versus the typical S-Cam drum brakes found on today's tractor-trailers. Current federal regulations require a 56,470-pound tractor-trailer going 60 mph to come to a full stop in 355 ft. Bailey said air disc brakes can achieve stop the same vehicle in 215 ft., a 39% improve over federal requirements.
He added that Bendix field-testing also shows air disc systems have better "hot brake" performance. Drum brakes lose 25% of their efficiency as they heat up from heavy use, something that Bailey said does not happen to air brake systems. He added that drum brakes require more air pressure, from 60-70 psi, when they heat up to between 636 to 672 degrees Fahrenheit. Conversely, air disc brakes need only 29-40 psi for activation at temperatures between 809 to 868 degrees Fahrenheit.