The De Dion Tube, a unique suspension system originally patented in 1894 for steam-powered De Dion Bouton vehicles, continues to find relevance in the 21st century. Its recent adoption in the 2023 Daimler-Fuso eCanter electric truck highlights the enduring ingenuity of this design. Let’s delve into the history and mechanics of the De Dion tube.
Distinguishing Features of the De Dion Tube
While technically a non-independent beam axle, the De Dion tube distinguishes itself from traditional designs. Unlike conventional beam axles where half-shafts reside within the axle tube, the De Dion tube positions them externally. Furthermore, the final drive differential is mounted on the chassis, connecting to the wheel hubs via half-shafts with flexible sliding joints. This setup offers unique advantages in terms of unsprung weight and handling characteristics.
Origins and Early Adoption
Named after Comte Jules-Albert de Dion, founder of De Dion-Bouton, the De Dion tube was actually the brainchild of co-founder Charles Trépardoux. Designed initially for rear-mounted steam engines, the system proved adaptable when De Dion Bouton transitioned to petrol power. Trépardoux’s design allowed for a chassis-mounted final drive connected to a leaf-sprung beam axle, a configuration that persisted even with the shift to front-mounted engines. While other manufacturers embraced chain or belt drives, De Dion Bouton retained the De Dion tube.
Resurgence in Racing and Performance Cars
Following a period of dormancy, the De Dion tube experienced a resurgence in the mid-20th century, finding favor among racing and performance car manufacturers. Pioneering figures like Harry Miller, a renowned American race car builder, incorporated the De Dion tube into front-wheel-drive and all-wheel-drive racing cars. This renewed interest stemmed from the De Dion tube’s ability to offer superior handling and reduced unsprung weight compared to live axles and swing axles. Notable manufacturers like Alfa Romeo embraced the De Dion tube, integrating it into various models like the Alfetta, GTV6, and Milano.
From Alfa Romeo to Electric Trucks
Alfa Romeo stands out as a high-volume adopter of the De Dion tube, but other manufacturers also utilized this suspension system. Lancia, Mazda, Volvo, and even Chrysler in their all-wheel-drive minivans incorporated the De Dion tube. The Lotus Seven and various Aston Martin models also benefited from its unique characteristics. The advantages of reduced unsprung weight and improved handling made the De Dion tube a compelling choice for diverse applications.
Advantages and Disadvantages of the De Dion Tube
The De Dion tube offers significant advantages, particularly its lower unsprung weight compared to live axles. This translates to improved ride quality, handling, and tire contact with the road. However, the complexity and cost of the De Dion tube, especially with coil or torsion bar spring setups requiring additional components like radius rods and Panhard rods, contributed to its decline in favor of simpler independent rear suspensions.
The De Dion Tube in the Electric Era
Just as it seemed destined for obsolescence, the De Dion tube found a new niche in the age of electric vehicles. The emergence of eAxles, integrated electric motor and final drive units, presented challenges related to increased unsprung weight and vibration. Daimler-Fuso’s use of a De Dion tube in the eCanter addresses these concerns by keeping the heavy eAxle components off the unsprung mass.
The De Dion tube, a suspension solution with a rich history, continues to demonstrate its adaptability and relevance in the ever-evolving automotive landscape. From its origins in steam-powered vehicles to its modern application in electric trucks, the De Dion tube stands as a testament to enduring engineering principles.
