3. 1976-77 Tyrrell P34
This is the only six-wheeled car to ever race in F1. It actually won a race, too. The idea was that you could have the same traction as a tire twice as wide, with half the wind resistance. Ironically, the only problem was that no one copied the design, so Goodyear had little reason to improve the tires, which ultimately rendered the car obsolete.