THE SHIFT to air disc brakes on heavy-duty trucks in North America won't occur overnight, but it will happen. Air disc brakes already hold 80% of the commercial truck market in Europe.
This was one of the key points made by senior managers of Bendix Spicer Foundation Brake LLC during a February press conference in Sandestin, Florida. Launched last year, the Bendix Spicer Foundation Brake joint venture claims to be the largest air disc brake manufacturer in the world when Bendix European affiliate Knorr-Bremse is included.
“We're in a period of transition to air disc brakes, but drum brakes will be with us for a long time to come,” said Kishor Pendse, president of Bendix Spicer Foundation Brake LLC. “Demand for air disc brakes is not driven by regulation in the North American market, and they will continue to be seen as premium products for the time being.”
Pendse said that air disc brakes command a premium of about $200 over drum brakes at this time. The premium must fall below $100 to spur demand. “We could reach the $100 range in about a year, depending on market response,” he said.
Despite the slow growth in demand for air disc brakes, the Bendix Spicer team is optimistic about the future. In fact, they have enough confidence in the product that the joint venture plans to build a plant for air disc brakes in Frankfort, Kentucky, in 2005. The plant will turn out 120,000 brakes a year.
“We know that demand will grow, and we're going to be ready,” said Bill Mossing, assistant general manager of Bendix Spicer Foundation Brake. “Major fleets will be a driving force in the transition to air disc brakes, and we believe the shift will take 10 to 15 years.
“Initially, most of the potential for air disc brakes will be on the steering axles. In fact, Paccar has now listed air disc brakes as a published option for the steering axle position on their trucks. However, we're also seeing interest from Canadian fleets for air disc brake installations on tank trailers.”
Numerous benefits
Bendix Spicer officials said more trucking companies would give serious consideration to air disc brakes once they know more about the benefits. And there are plenty of benefits to talk about.
First and foremost, air disc brakes reduce stopping distances by nearly 40%, compared with drum brakes on heavy-duty trucks. The inherent high efficiency (95%) and low hysteresis (<9%) of the Bendix air disc brake system mean there is a negligible difference between left and right side brake performance. Pressure is applied constantly and efficiently to all wheels, which makes it easier for the vehicle to come to a straight, stable stop.
Brake fade is virtually eliminated with air disc brakes. Bendix air disc brakes were tested in Colorado on a mountainous section of I-70. The eight-mile stretch of highway included a 7% grade. Brake fade was nil, and there was no degradation in stopping power.
New field test data from Bendix Spicer Foundation Brake suggests that an air disc brake-equipped tractor and drum brake-equipped trailer experience no accelerated wear of either the tractor disc pads or trailer brake linings.
Drum brake commitment
While touting air disc brakes for the future, Bendix Spicer officials stressed that the company remains fully committed to the drum brakes that currently dominate the heavy-duty truck market in North America. Drum brakes account for 95% of the heavy-duty truck market in the United States. The brakes are the lowest in cost, are reliable, and customers have decades of experience with them.
Jim Clark, center of competency director for drum brakes at Bendix Spicer Foundation Brake, stressed that the joint venture differentiates itself in the market with its single anchor pin design for drum brake products. The premium single anchor pin product currently is standard on truck and tractor applications and optional on trailers.
Single anchor pin product features include the following:
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Reduced component stresses due to a larger anchor pin diameter and the cancellation of shoe forces within the pin (not in the spider/torque plate).
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Superior internal geometry control with a fixed anchor pin.
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A patented “hot-staked” shoe manufacturing process for improved quality and reduced structural fatigue.
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Reduced lining-to-drum pressures due to longer lining arc.
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Premium, exclusive brake lining formulas for longer life, including new “transfer film” technology linings.
All of these factors have played a role in reducing the lifetime operating costs of drum brakes. “It's getting to the point where the first owner won't need to do a brake reline,” Clark said. “We'll be even closer to that goal with a new product coming out later this year.”
Drum brakes will still be able to meet the stopping distances that would be mandated in a rulemaking that is under development at the Department of Transportation. The proposal calls for a 30% reduction in the current stopping distance for heavy-duty trucks.
Aftermarket parts
In addition to discussing the latest brake developments for heavy-duty trucks, Bendix Spicer officials provided an update on the joint venture. They stressed that both parent companies will continue to be involved in research and development and manufacturing.
Between 65% and 70% of the joint venture's current sales are to original equipment truck and trailer manufacturers. Only about 30% of the sales are to the aftermarket sector. “We see significant growth opportunities in aftermarket parts,” Mossing said.
Original equipment and aftermarket truck parts sales will be handled by the Bendix sales force. The Dana sales team will focus on trailer original equipment makers. The Roadranger network will take care of field sales to fleets and dealers.
In the future, the majority of aftermarket products available through Bendix Spicer Foundation Brake will carry the Bendix name. While the Spicer brand is well known throughout North America, the brand will have very restricted use in the joint venture. Parts distribution has been consolidated into the Bendix warehouse center in Huntington, Indiana.