The test mule for Mupo suspension: Moto Morini Granpasso R.

After an entire century of research on suspension, today’s most advanced system is the semi-active suspension found on race bikes like the BMW HP4. Magneto-Rheological suspension is the next step in keeping motorcycle riders impervious to road conditions. Magneto-Rheological suspension has been prevalent in four wheeler suspension technology for quite some time now. Manufacturers like Ferrari, Lamborghini and Audi use this kind of suspension on their top-shelf performance cars. This technology is not yet introduced in the motorcycle industry, but things are about to change. Mupo Srl, a racing suspension manufacturer based out of Motor Valley, recently debuted a new magneto-rheological suspension sysem aboard a Moto Morini Granpasso R.

The Principle

In traditional forks and struts, the damping is achieved in principle by a change in the flow of damper oil inside the cylinder. A magneto-rheological setup instead alters the viscosity of the oil itself. The oil in question is the so-called magneto-rheological fluid interspersed with microscopic metal particles that can be electrically polarized. The function of the piston is carried out by electromagnets, which create a specific magnetic field inside the fork or shock, fed by an electrical connection. The metal particles in the fluid start aligning themselves according to the field, thus thickening the fluid. The more particles enter the magnetic field, the thicker the fluid becomes. “The fluid is incredibly versatile,” explains Professor Antonio Pietrosanto of the University of Salerno, who co-developed the system. “It can flow as easily as water, but it can be as hard and impenetrable as cement.”


The Hardware

Professor Pietrosanto began research on the suspension back in 2006. The team floated a new company under the University of Salerno, called Spring Off. The sole aim of the company engineers was to create, and above all to control appropriate magnetic fields. The result of Spring Off is now a control unit, which contains the electrical circuits as well as the software that measures the state of the spring elements. This eliminates the need for other sensors placed on various parts of the motorcycle. Depending on the input, the control unit powers up the magnets. The controlled magnetic field is altered accordingly and the suitable strength of damping is thus achieved.

Mupo-Magneto-Rheological-Suspension The fork and strut communicate with each other via the control unit’s electrical circuits, making the damping transitions seamless and fast. “We have 1,000 control cycles per second,” explains Professor Pietrosanto. “This makes us faster than other semi-active systems that work mechanically.”

The Application

The magneto-rheological suspension has one drawback though: over a few kilometers of undisturbed riding, the magnetic particles tend to settle down. As the suspension starts tackling rough terrain, these particles must first mix evenly in the fluid to return to function. The first few moments will be hairy, but then the suspension will come into its own, and the bike will make rapid, steady progress; seemingly floating with impunity over the worst of surfaces. Theoretically, the deeper the pothole and higher the speed, the better the suspension will damp the jolt.


The preset inputs for various types of surfaces can also be programmed into the control unit by a special app, opening the possibility of tailor-made suspension on every motorcycle on the road.

Magneto-rheological suspension seems like a foolproof kind of technology that would make motorcycles incredibly more comfortable and safer. However, this kind of tech has a price. Mupo Magneto is available in Germany, retailing for $4,125. The kit consists of the cartridge for the fork, strut, the control unit and wiring.