FORGOTTEN MOTOCROSS TECH: RIBI QUADRILATERAL LINKAGE FORKS
Motocross history is filled with creative ideas that were heralded as ground-breaking, some were abandoned, others stupid and a few were truly innovative. Do you remember the Ribi Quadrilateral Forks?
Back in the late 1970s Valentino Ribi was a young inventor with a love for motocross. Valentino was concerned about the effects of geometry change when the suspension of a motorcycle collapsed…and he thought he had a better idea. With the help of Roger DeCoster, who did the test riding, Valentino built a linkage front fork that used rear shock absorbers to handle the suspension chores and folding linkage, a la leading links, to trace his desired arc for the front wheel.
Roger DeCoster tested the fork and believed in it so much that he put it on his works Suzuki and raced the 1979 500cc World Championships on it. The fork was so much of a prototype that when DeCoster showed up at the first GP the chromoly fork wasn’t even painted.
After Roger left Team Suzuki and moved to Team Honda, he encouraged Honda to pursue the development of the Ribi Quadrilateral forks. Honda bought the rights to the design and built several very exotic, CNC-machined, aluminum versions—including a single shock version. But, unfortunately, Honda shelved the idea because of its complexity.