Volvo’s Sprung ADTs and the Evolution of Articulated Hauler Suspension

Volvo Construction Equipment has long been a pioneer in the articulated dump truck (ADT) segment, having introduced the world’s first ADT—the DR631—in 1966. Traditionally, ADTs relied on rigid rear frames and large, low-pressure tires to absorb terrain shocks. However, as jobsite demands increased and operator comfort became a priority, Volvo began integrating suspension systems into its ADT lineup. The introduction of sprung rear axles marked a significant departure from the rigid norm, aiming to improve ride quality, reduce operator fatigue, and enhance machine longevity.

Understanding Sprung vs. Rigid Rear Ends

In a conventional rigid rear-end ADT, the rear axle is bolted directly to the frame. This design is simple, durable, and effective in absorbing shock through tire flex and frame articulation. However, it transmits significant vibration to the operator and can cause bouncing or instability at higher speeds or on uneven terrain.

A sprung rear end, by contrast, incorporates suspension components—typically hydraulic cylinders, nitrogen accumulators, or mechanical springs—between the axle and frame. This allows the rear wheels to move independently over obstacles, smoothing the ride and reducing stress on the chassis.

Benefits of Sprung Rear Suspension

Operators and fleet managers have reported several advantages:

• Improved ride comfort: Especially noticeable at higher speeds or on long hauls
• Reduced frame stress: Suspension absorbs impact that would otherwise transfer to welds and joints
• Better tire contact: Suspension keeps wheels planted, improving traction and reducing tire wear
• Higher productivity: Operators can maintain speed over rough terrain without compromising control

One operator in Alberta noted that his crew could run the new Volvo A35E with sprung rear suspension 15% faster on haul roads without spilling loads or bottoming out.

Concerns and Trade-Offs

Despite the benefits, some concerns remain:

• Increased complexity: More moving parts mean more potential failure points
• Maintenance requirements: Suspension components require inspection and occasional nitrogen charging
• Cost: Sprung models carry a higher purchase price and may have higher long-term maintenance costs
• Perceived softness: Some operators feel that sprung trucks “float” too much, especially when fully loaded on steep grades

A mechanic in Finland shared a story of a sprung Volvo ADT that developed a nitrogen leak in one accumulator. The result was uneven suspension response and increased tire wear on one side. After replacing the accumulator and recalibrating the system, the issue was resolved—but it highlighted the need for regular checks.

Volvo’s Suspension Strategy

Volvo’s approach to suspension is modular. On newer models like the A35G and A45G, the front axle is fully suspended using hydraulic cylinders, while the rear axle can be either rigid or suspended depending on configuration. This allows customers to choose based on terrain, haul distance, and budget.

Volvo also integrates automatic leveling and load compensation into its suspension systems. Sensors detect load weight and adjust damping accordingly, ensuring consistent performance whether empty or fully loaded.

Operator Feedback and Market Trends

Feedback from operators has been largely positive. Many report reduced fatigue during long shifts and better control on downhill grades. In Scandinavian markets, where haul roads are often icy or uneven, sprung ADTs have become the standard.

Manufacturers like Bell and Caterpillar have also introduced suspension systems in their ADTs, signaling an industry-wide shift. As telematics and predictive maintenance become more common, the complexity of suspension systems becomes less of a barrier.

Final Thoughts

Volvo’s adoption of sprung rear suspension in its articulated dump trucks represents a thoughtful evolution in off-road hauling. While not without trade-offs, the benefits in comfort, control, and productivity are clear. As jobsite expectations rise and operator retention becomes more critical, features like suspension may soon become standard rather than optional. For those hauling long distances over rough terrain, the investment in a sprung ADT could pay dividends in uptime, safety, and operator satisfaction.