Trucks at Work
Betting on better brakes

Betting on better brakes

When you add up the attributes, we think it‘s the way to go.” -Jerry Warmkessel, marketing product manager, Mack Trucks

So I attended a press conference yesterday to learn that Mack Trucks is now offering Bendix‘s ADB22X air disc brakes the steer and drive axles of its Pinnacle Axle Forward and Axle Back tractor models, as well as on its Granite vocational truck product, as optional equipment. Now, air disc brakes are more expensive than the traditional drum brakes used by the trucking industry for decades - WAY more expensive - but Jerry Warmkessel, for one, believes that cost should be outweighed by all the benefits air disc brakes bring to the table.


(Bendix's air brake for heavy trucks.)

Jerry‘s old school, by the way - meaning he doesn‘t dabble in snake oil or fancy pitches, despite having the word “marketing” in his title. He was awarded a Silver Spark Plug by the Technology & Maintenance Council back in 2004 - the group‘s highest honor - in recognition for years of tireless service (he joined TMC in 1989) developing standards in partnership with fleet managers to make the industry‘s equipment better for everyone, not just Mack.

So when he came right out and said air disc brakes can cost 50% to 80% more per axle than drum brakes - with front disc brakes lower in cost as they are less complex - you know he‘s a straight shooter. Despite that higher initial price, Jerry thinks there are some serious savings fleets can achieve by switching completely to air disc brakes - outside of their biggest advantages, which are more stopping power and better braking in poor weather conditions.

[I‘ll let Jerry explain the safety and maintenance benefits himself: just click on the video below.]

The reason braking systems are being debated in trucking right now is pretty straightforward: new federal stopping distance requirements that should go into effect later this fall. Finalized in March 2007, the new rules promulgated by the National Highway Traffic Safety Administration (NHTSA) cuts by 30% the amount of distance a Class 8 tractor gets to come to a complete stop from 60 mph. By 2009, all new three-axle tractors must comply with this new requirement - about 80% of all new tractor air-brake production - followed by specialty tractors in 2011.


(Mack's Pinnacle tractor.)

So fleets have a choice - go with beefed up drum brakes designs or switch over the air disc brakes. Weight is the first hurdle to cross: while air disc brakes weigh slightly more than current drum brake packages (a fully air disc tractor system weighs 11 pounds more compared to one equipped with drums) the new wider drums needed to meet the new federal standards surpass the weight of air discs. Go with air disc over those wider drums and the truck slims down by 158 pounds - a pretty significant drop, says Jerry.

The other big savings comes on the maintenance side of the ledger. Air disc brake pads are easier to change out and last a lot longer than drum brakes. A Mack fleet that Jerry knows that runs all disc brakes on its tractor units reports that when they sell their trucks at 600,000 miles, 90% still have the original air disc pads in them.

Air disc brakes also self-adjust, bypassing a major out-of-service problem for many truckers. In its annual brake inspection safety blitz this year, the Commercial Vehicle Safety Alliance (CVSA) reported that 9.9% of the 11,908 vehicles inspected were placed out of service for brake adjustment defects.


(Mack's Granite vocational truck.)

“Poorly adjusted or defective air brakes reduce the braking capacity of large vehicles and further increase their stopping distance,” said CVSA‘s Executive Director Stephen Campbell. “Even under ideal conditions, the stopping distance of commercial vehicles can be twice as far as that of cars and other smaller vehicles.”

Air brakes have a compelling story to tell - but will the price differential prove too much to overcome? That will be the big question as air disc brakes begin to position themselves in the market.