FORGOTTEN MOTOCROSS TECH: HOW TO MAKE IT FASTER — BY LEVELING IT OUT

Have you ever wondered if you could make your bike handle better? Preston Petty did. Preston felt that if he could control the big swings in motion that a bike makes under braking, he could find a frame geometry and balance that would make the bike easier to ride and more stable. His idea? No-dive front forks. Here, it is being tested on Broc Glover’s bike.

Motocross history is filled with examples of creative ideas that were heralded as groundbreaking, but, because of the rapid rate of change in development, sank into the swamp of forgotten technology. Although some are best left abandoned, others were truly innovative (if not ultimately successful). MXA loves to reveal motocross’ tech trivia. Do you remember this idea? The Preston Petty’s No-Dive system.

Racers from the ’60s remember Preston Petty as one of America’s fastest riders. Racers from the ’70s know him as the man who invented the plastic fender. Racers from the ’80s think of him as being responsible for the injection-molded enduro headlight, Tuff Tub, plastic skid plate and Petty hex grip. And, had the world been a more advanced place, riders from the ’90s would have remembered Preston for inventing the Preston Petty No-Dive.

Shown above on Broc Glover’s works Yamaha, the Petty No-Dive was a lever arm that attached to the front fork with a heim-jointed strut transmitting force to the triple clamps. Under hard braking, a Petty-No-Dive-equipped bike would not dive. The concept was to keep the frame geometry the same (head angle, trail and wheelbase) so that the rider could work from a stable platform.

Roger DeCoster testing the Preston Petty No-Dive in the sand at Indian Dunes.

Although the Petty No-Dive was used and tested by Roger DeCoster (seen above on his works Suzuki), Broc Glover, Brad Lackey and Kent Howerton, it never caught on in motocross. It was, however, a standard feature on many road race bikes of the late ’80s and ’90s. Unfortunately for Preston, the manufacturers didn’t buy his patent, but instead took his concept and made it a hydraulic feature of their forks. Today, Preston lives a quiet life as a computer programmer and spends his spare time developing electric race bikes.

The Preston Petty No-Dive was a torque arm that lessened front end dive under hard braking. This is Roger DeCoster’s bike. Preston patented the idea and produced it. The retail price was $60. But, the Japanese manufacturers realized that they could achieve the same thing hydraulically in the forks and used the hydraulic no-dive concept on their road race bikes. Although it never found much success in motocross, it was used by offroad great Carl Cranke in the ISDT.

Steve Whitelock mounts a Preston Petty No-Dive on Brad Lackey’s works Honda. The idea had promise and virtually every team ran a test program on it, but few elected to run it. Perhaps because their frame geometry was setup to work with dive, while the full implementation of Preston’s concept would have required a different head angle.

 

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