Fleet Management News & Business Info | Commercial Carrier Journal
Issue link: http://read.dmtmag.com/i/538378
54 COMMERCIAL CARRIER JOURNAL | JULY 2015 O f the two brake options available for heavy- duty trucks today, air disc brakes generally are considered to be the more elegant choice based on their inherent design advantages and simplifi ed mainte- nance demands. In 2013, when new federal stopping distance regulations for heavy trucks became law, many in the industry thought that a push toward wide- spread air disc adoption by fl eets was a sure thing. But while their market share has increased since those regula- tions came into effect, drum brakes continue to dominate the industry. Air disc brakes already are com- mon in Europe, says Nicole Oreskovic, product manager of air disc brakes for Bendix. In North America, however, they traditionally have been consid- ered a niche technology best suited for bus, coach, fi re truck and other specialty applications. At the height of their market domi- nation ahead of the 2013 stopping dis- tance regulations, drum brakes in the heavy commercial truck market held a commanding 94 percent share, with air disc brakes making up the rest. Those fi gures have changed some- what since 2013. Some fl eets opted to switch to air disc brakes in order to meet the new guidelines, and OEMs now offer more air disc products as both standard and optional equip- ment on new tractors. "Today, air disc brakes continue to grow as an overall percentage of the market, with power units leading trail- ers," says Bill Hicks, product planning, trailer suspension systems, SAF- Holland. "Overall, a general number of 10 percent market share overall is considered to be a reasonable estimate for air disc penetration today, with the front steer axle leading the way." Regulatory push The federal standards in question re- quired a signifi cant increase in braking performance. According to the 1995 Federal Motor Vehicle Safety Stan- dard issued by the National Highway Transportation Safety Administra- tion, stopping distance requirements varied according to vehicle type, with most Class 8 tractors required to stop within 355 feet when tested at 60 mph while pulling an unbraked control trailer in the loaded-to-gross vehicle weight rating condition. Unloaded tractor-trailers were required to stop within 335 feet. The new regulations, which came into effect in August 2013, require un- loaded heavy trucks to stop 30 percent sooner than under the old braking guidelines. In practical terms, this requires a Class 8 tractor to come to a full and complete stop from 60 mph in 235 feet. "That's a pretty dramatic increase," Oreskovic says. "But NHTSA felt it was an achievable goal without put- ting undue stress on the trucking industry thanks to improved braking technology. The performance of air disc brakes was a key factor in the agency reaching that conclusion." Air disc brake systems continue to make Class 8 inroads. Can your fleet benefit as well? BY JACK ROBERTS Air disc brake market share penetration increases every year. – Randy Petresh, vice president of technical services, Haldex By using air disc brakes, maintenance downtime can be reduced because brake pads may last up to twice as long as drum linings.