With limited production set to start next April, Dana Corp. has released technical details for a new heavy-duty air-ride suspension that combines a single taper leaf spring with a new air spring and a patented roll control device. The company says its new FrontRunner will offer the handling characteristics of a taper leaf spring with the comfort of air springs, while also improving front brake performance.
The first model to be released is intended for over-the-road set-back axle tractors with long sleepers. It will incorporate Dana’s E-1202W 12,000-lb. steer axle and is said to weigh 75 lbs. less than a comparable leaf spring suspension. Once full production begins in late 2006, Dana says it expects to add additional models for other applications.
By using both leaf and air springs, the suspension provides drivers with familiar steering response and lateral stability while also improving straight-line tracking and smoothing out the ride, according to Mark Davis, steer axle product manager for Dana. The design also allows truck builders to fine-tune roll stiffness and ride characteristics for specific truck models, he says.
In addition to the spring combination, the FrontRunner includes a patented brake reaction link that limits “wind up” of the leaf spring on braking and will allow the suspension to handle higher braking loads that could come with new regulations calling for shorter stopping distances for trucks. Additionally a patented torque control tube can be optimized for roll resistance without affecting ride characteristics, according to Dana.
The new suspension is compatible with most current steer axles and wheel-end components, including low-maintenance hub assemblies, 16.5-in drum brakes and air-disc brakes. It also fits on most truck chassis with minimal modification, simplifying transition to the air suspension for truck makers.
Currently Dana is field testing the FrontRunner on International 9400i and Peterbilt 387 tractors. Once in full production, Dana expects it to be available through “multiple OEMs,” according to Davis, at a cost “somewhat higher than a traditional leaf spring suspension.”
