Duane Flatmo's "Badass", the bike that shouldn't be.
The front-wheel-drive, rear-steer bicycle is widely considered to be impossible to ride and has been tried and abandoned by just about every freakbiker I know.
The perceived impossibility has to do with the physics of what makes abike ride. Contrary to popular belief, gyroscopic forces play no role in a bike'sstaying upright. The secret is in the "trail" of the fork, or thedifference between a line through the headtube and the placement of theaxle. A wheel with no trail drives like a bus. A wheel with negativetrail is a smart caster. Rake causes trail, along with the curve in thefork.Because of the trail, a moving bicycle that falls slightly to one side hasits center of gravity shifted slightly to the other side, and all on itsown the bike falls back to upright. This is why you can ride no-handed.Rear-wheel steering is precarious on any vehicle, deadly at high speeds, and itreverses this relationship. As the bike makes a turn, in theory, thecenter of gravity is shifted *outside* the line between the wheels and thebike falls over. That is exactly my experience with every one I've everseen.
From wikipedia's "bicycle dynamics"article:
"Rear-wheel steeringBecause of the theoretical benefits, especially a simplified front-wheeldrive mechanism, attempts have been made to construct a ridable rear-wheelsteering bike. The Bendix Company built a rear-wheel steering bicycle, andthe U.S. Department of Transportation commissioned the construction of arear-wheel steering motorcycle: both proved to be unrideable. RainbowTrainers, Inc. in Alton, IL, offered US$5,000 to the first person "who cansuccessfully ride the rear-steered bicycle, Rear Steered Bicycle I".Examination of the eigenvalues [studies of the physics of bike riding]shows that the rear-wheel steering configuration is inherently unstable."And yet: