When it comes to unusual vehicles, Bring A Trailer never disappoints. A perfect example is this 1970 Rokon Trail Breaker, a dirtbike oddity from the '70s with massive tires, two-wheel-drive, and interesting provenance. The Trail Breaker forgoes and kind of suspension in favor of a rigid frame and front fork in order to power the front and rear wheels via a dual chain drive system. A 136cc Chrysler Power Bee puts 10 horsepower (when new) to an Albion three-speed transmission and on to both wheels. The aluminum wheels are hollow, and combined with the large tires, allow the Trail Breaker to float — a feature you won't find on many motorcycles. This bike was supposedly purchased new by Dr. Forrest Bird, who invented the modern medical ventilator, adding a bit of history an rare motorcycle.