LaBastide adds, “Air disc brakes have a substantially higher initial cost, but are easier to maintain, assuming you are only doing maintenance like pad changes. Most air disc brake calipers are sealed and non-serviceable, so if the caliper internals fail, you need to replace the complete caliper assembly. So far, the latest generation of air disc brakes has performed very well.”
The increased cost of air disc brakes must be factored into the life-cycle cost. “When you factor in the added acquisition cost and you total that against increased service times and overall maintenance costs, the longer the owner holds onto the vehicle, the more favorable the disc brake solution becomes,” says Ganaway.
The weight difference between air disc and drum brakes is almost insignificant. “This can vary depending upon the equipment, but they are a few pounds lighter to weight-neutral compared to drum brakes,” says Dorwart.
According to Haggai, the air disc brake system performs well, but may not be the best option over a properly spec’d drum setup for vocational customers. “In most applications, the vocational user may not realize a measurable return on the additional cost of the disc system,” he asserts.
The air brake system is versatile, but you need to consider your application. “Air disc brakes can virtually be used in any application, including the construction vocation,” says LaBastide. “One air disc brake manufacturer utilizes one brake for all applications and different rotors. Another manufacturer utilizes different brake sizes and lining material and customizes those attributes to each application.”
Some precautions need to be taken on muddy jobsites or when working around wet concrete. “You have to use caution when using air disc brakes in these environments by hosing down the wheel ends,” says Ganaway. “The air disc brake is a robust product, but it is not a maintenance-free product. Those types of application environments just enhance the need to ensure some components don’t have dirt ingress or concrete ingress.”
Benefits outweigh costs
The RSD brakes are going to add a little cost and weight up front, but increased braking performance and service life may offset any potential drawbacks.
“In an industry that watches cost and weight very closely, this regulation may have some impact,” Haggai says. “However, increased braking performance and lining life may provide dividends in the long run.”
The first phase of the regulations should have minimal effect on the industry. “I don’t expect much impact on the purchase plans of fleets,” says LaBastide. “The cost penalties have been minimal except with the air disc brakes, which again are optional for Phase I of the regulations. Phase II is a different story though. I expect to see more air disc brakes and even six-channel ABS being required on those units in the Phase II categories.”