Front Suspensions

FRONT SUSPENSIONS

HOW Motorcycles WORK 9

STEVE ANDERSON

CHANGE IS IN THE air. It's only a faint scent now, only a first hint. But that odor of revolution is here, presaging things to come.

For 30 years now, there has been one standard for motorcycle front suspensions: the telescopic fork. Perhaps there have been slight differences, as some manufacturers located springs inside the fork tubes while others placed them on the outside, or as some companies used air as a springing medium while others disdained it. But, in es sence, almost every motorcy cle front suspension in this time period has been some version of a plunger based on concentric tubes. In this de sign, top tubes are clamped tightly to plates that pivot about the steering head: the bottom tubes carry the wheel and axle, and are free to slide up and down, controlled only by springs and hydraulic damping.

Much refinement has gone into this concept, resulting in increased stiffness, reduced friction, and improved qua! ity of damping and front wheel control. But telescopic forks are inherently rather heavy for a given strength or stiffness: and their sliding tube design ensures that fric tion will always be an issue.

So in recent years. innova tive designers have attempted alternatives to the telescopic fork, alternatives that seek to offer improvements in front suspension and handling per formance without extracting new penalties. So far, these have been experiments re served only for racetracks, but in the future, they might be seen on American streets. Even if that comes to pass, though, telescopic forks won't disappear; they're too much a part of the traditional motorcycle look.

With that in mind, we present a review of all com monly known front suspen sions. First we'll look in detail at the current standard, then we'll take a glimpse at systems that just might set the stan dards of the future.