Mack Trucks on Monday introduced its S852 tandem drive axles with an 85,000-lb. gross axle weight rating.
Roy Horton, Mack Trucks director of product strategy, said customers in Mack’s export markets expressed interest in the new rating, where local applications require a heavier-duty axle, but customers in North America will also be able to spec the 85,000-lb. rated axle for specialized severe-duty or heavy-haul applications on Mack Granite models. For extreme loads at slow speeds, the S852 tandem drive axles have a creep rating of 105,000 lbs.
Mack’s proprietary drive axles are engineered with a double-reduction design and include the use of Durapoid bevel and helical gears, which provide a favorable gear tooth geometry that helps eliminate localized stress and loading on the gear tooth end while also providing enhanced strength and longer gear life. Frictional losses are also reduced in this gear design, allowing Mack axles to deliver up to 1.5 percent improved fuel efficiency.
“Low-traction situations can be a challenge for truck drivers, seriously impacting their productivity,” said Horton. “To help address that issue, we offer standard inter-axle and optional inter-wheel power dividers that automatically distribute torque between the slipping and non-slipping axle or wheel respectively. This elegant engineering solution is proven and reliable and requires no intervention from the driver.”
Mack proprietary axles also feature a top-mounted carrier design that is not only less prone to main seal leaks, but also provides more than two inches of additional ground clearance. This gives customers improved maneuverability at construction sites and other off-highway applications.
An additional benefit of Mack’s top-mounted carrier design is improved driveline angles between the drive axles. Instead of a three and a half to eight-degree angle, Mack’s prop shaft angle is just one to two degrees. This maximizes universal joint life, allows for greater axle articulation and reduces vibrations for a smoother ride. It also reduces torque losses for improved efficiency.