Hydrolastic Suspension

The Moulton Hydrolastic suspension was first featured in the Morris 1100. This photo shows Alex Moulton with Alec Issigonis, who famously designed the Mini, at the lauch of the 1100 in 1962. In the background, is a chart detailing the design of the Hydrolastic suspension unit. The Hydrolastic was a rubber suspension unit with integrated fluid damping. It was important for two reasons. Firstly, whereas a conventional suspension used separate springs and dampers, the Hydrolastic combined the two, thus saving space. Secondly, the front and rear units were interconnected by a small diameter pipe, to reduce the tendency of a car to pitch when it went over a bump. The Hydrolastic suspension was used in several cars from the 1100, to the Rover 100 and Metro. It was originally intended to be featured on the Mini, but wasn't quite ready when the Mini was launched. The first Minis with Hydrolastic suspension were produced in 1964. A new implementation of the Hydrolastic suspension concept is currently in use in the Moulton New Series bicycle. Here, the fluid damped rubber unit contributes to the ultra smooth suspension. The stiffness of the rear suspension can be increased for heavier loads, by pumping air into the valve at the rear of the unit. Earlier New Series models also featured a valve on the side of the Hydrolastic unit for adjusting the fluid damping, but this is not a feature of recent models. Photo credits: Ken Butterfield and Alex Moulton Bicycles.