A de Dion tube is an automobile suspension technology. It was a primitive form of independent suspension and was seen as an improvement over the alternative swing axle type. A de Dion suspension uses universal joints at both the wheel hubs and differential, and uses a solid rod to hold the opposite wheels in parallel. Unlike an anti-roll bar, a de Dion tube is not connected to the chassis and is not intended to flex.

The benefits of a de Dion suspension include:

1. Reduced unsprung weight since the differential is connected to the chassis
2. No camber changes on suspension unloading (or rebound)

There were costs, however:

1. The de Dion tube itself and the extra universal joints add unsprung weight
2. A lateral location link (like a Panhard rod) is still needed
3. Sympathetic camber changes on opposite wheels are seen on single-wheel suspension compression

de Dion tubes were considered exotic and were rarely used. The original Mazda Cosmo, Alfa Romeo GTV6, and Rover SD1 are examples.

de Dion suspension characteristics: Camber change on bumps, none on rebound