BIKES YOU’VE NEVER SEEN BEFORE: 1990 DRYSDALE DRYVTECH 250

Motocross history is filled with examples of creative ideas that were heralded as groundbreaking—two-wheel-drive dirt bikes have been a fertile ground for innovation. It started with the Rokon Trail-Breaker, was expanded by the Savard brothers rally bikes and reached refined version with the Ohlins-designed Yamaha 2-Trac and brought to the masses by Christini. MXA loves to reveal motocross’ tech trivia. Do you remember the bizarre 1990 Drysdale Dryvtech 2x2x2? The strange-looking 1990 Dryvtech (drive-tech) machine was made by the Drysdale Motorcycle Company in Australia.

It was the brainchild of Australian motorcycle designer Ian Drysdale. Not only did it have hydraulic two-wheel-drive, but it was also equipped with rear-wheel steering. It was powered by a Maico 250cc engine with special crankcases to engage the Vickers’ 9-piston, hydraulic pump that could turn the front wheel only or both the front and rear together.

The Maico engine powered the Vickers hydraulic pump and the fluid was pressurized the to 4500 psi. The hydraulic fluid ran through steel tubing to drive the front and rear center0hub wheels. the front and rear wheels

The positive-displacement hydraulic pump pressurized the fluid to 4500 psi, then sent the fluid to hydraulic motors in each wheel. The highly pressurized fluid was routed down steel tubes that follow the bike’s front and rear swingarms, using a complex concentric pivot to follow the angle of the swingarm without releasing the pressure.

Where most 2WD dirt bike designs channel 5 to 10 percent of the total power to the front wheel, the Dryvtech bike is totally tuneable using a pressure reducing valve. The center-hub steering works via one-sided swingarms, but there is a delay mechanism that separates front and rear steering—5 degrees of handlebar input is necessary before the rear begins to turn. This prototype never went into production but sold twice to collectors, once for $25,000 and once for $7037.