Motorcycle Maintenance

Active versus Semi-Active Suspension | Ask the Geek

I love F1 Racing, car technology, and how all of it ends up in sportbikes. Can you explain how the dynamic damping control and semi-active suspension varies from active suspension that was outlawed in F1 Racing in 1993? Does the BMW HP4 have active suspension, since it measures conditions at 100 hertz? Is the technology any different between the 2013 BMW HP4 and the Ducati 1299?

I’m looking for my next bike, and it would be awesome to own some F1 tech. I have a 2013 BMW M3, which has dynamic damping control and an auto-blipper for downshifts—my next bike will definitely need these at a minimum.
Mike Jarvis
San Francisco, CA

Active suspension was first developed by Lotus in the ‘80s for Formula 1 and replaces the spring and damper with a hydraulic or electromagnetic actuator to control the wheel. In a conventional suspension setup, the ground pushes the wheel up and the spring pushes it down; in an active system, the actuator controls the wheel movement by literally lifting the wheel over bumps or pushing it down into dips, which keeps the chassis at a smooth, steady attitude. In a car, active suspension can be used to control pitch, roll, comfort, or any of the suspension’s characteristics, improving grip and comfort. The technology was banned from F1 after Nigel Mansell’s record-breaking 1992 season in a Williams equipped with active suspension. At the current state of the technology, active suspension is too heavy, bulky, and expensive for production automobile or motorcycle use.

BMW, HP4, Dynamic Damping Control, Suspension, electronic suspension adjustment

Photo Courtesy of BMW

BMW’s Dynamic Damping Control, as used on the HP4, is a semi-active system that alters damping much quicker than the Electronic Suspension Adjustment systems used on some of the company’s other models. None, however, are truly active suspension systems.

All the forms of electronic suspension currently used on production motorcycles use conventional spring and damper assemblies controlled by electronics. These can be divided into three groups. The first is electronically adjustable suspension, where stepper motors are used to turn the shock and fork external adjusters, essentially replacing the screwdriver and preload wrench. These include BMW’s Electronic Suspension Adjustment (I and II), the Ducati Electronic Suspension used on previous-generation Multistradas, and the setup found on Yamaha’s Super Ténéré ES. These systems allow the rider to choose a setup from the dash, but none make automatic adjustments as you ride.

The second group includes Öhlins Mechatronics and the Öhlins systems used on the Ducati 1299 Panigale S, Yamaha YZF-R1M, and MV Agusta F4 RR, and they can be considered semi-active. These systems also have stepper motors on the shock and fork to make adjustments electronically but rely on feedback from sensors on the bike to alter settings as you ride. The speed at which these systems can make a change is in the order of tenths of a second, so adjustments can be made (for example) based on speed and acceleration, for braking or cornering, and so on. Additionally, the rider can typically select an overall setup from the dashboard, opt for a generally stiffer or softer setup, or make individual settings changes in a manual mode.

The third group of electronic suspensions incorporate electronically controlled valves inside the shock and fork that can make a damping change much quicker—in the order of several thousandths of a second, as opposed to tenths of a second—making them closer in operation to fully active suspension but still semi-active. Systems currently in use include BMW’s Dynamic Damping Control (DDC) used on the HP4 and S 1000 RR and Ducati’s Skyhook Suspension (DSS) on the Multistrada models. These systems are capable of everything the previously mentioned setups are and more because of the extra speed available. For example, whereas the Öhlins Smart EC system used on the Ducati 1299 Panigale S can make adjustments based on general riding conditions or for an overall behavior desired by the rider, the company’s Skyhook Suspension can make adjustments for a given lean angle or even individual bumps in the road.

Read our in-depth look at the various types of semi-active suspension here: Semi-Active Suspension

To specifically answer your questions then, the BMW HP4’s Dynamic Damping Control is not fully active suspension, even though it can change damping so quickly. And the HP4 and Panigale’s systems are significantly different from each other in how (and how quickly) damping is changed, putting the two systems into different groups of semi-active suspension as we’ve defined them.

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