Mack Trucks has released the S852 tandem axles, which have an 85,000-lb. gross axle rating and are now available to spec on the Granite model for specialized severe-duty or heavy-haul applications. The creep rating is 105,000 lbs., used at ultra-slow speeds for vocational work such as on a construction site.
Along with providing brute support, the axles’ intricate gears interior design provides up to a 1.5% improvement in fuel efficiency.
“Mack has a long and rich history of engineering and manufacturing its own powertrain components, including drive axles, as it fits with our philosophy that components designed to work together, simply work better,” said Roy Horton, Mack Trucks director of product strategy. “We welcome the new S852, which will broaden the applications our trucks are built to handle.”
Mack noted that like their first axles engineered 120 years ago, these tandem axles use a double-reduction design, which “maximizes durability by reducing the speed from the drive shaft before transmitting torque to the axle shaft, as well as helping spread and balance loading over two gear sets.”
Other design features include Durapoid bevel and helical gears that geometrically mesh to curtail localized stress and loading on the gear tooth end. This enhances strength and promotes longer gear life, according to Mack. The previously mentioned fuel efficiency bump comes from reducing frictional loss.
The axles lighten the load on the driver as well.
“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.”
The top-mounted carrier design also brings about several advantages:
- Prevents main seal leaks and raises the ground clearance 2 inches for better maneuverability
- Allows for improved driveline angles between the axles for greater axle articulation
- Reduces vibrations and torque losses for improved efficiency
