The lower a recumbent is, the faster it is - the aerodynamic cross-section is smaller. This causes problems with recumbent design, though - with a rear-wheel-drive bike, the chain has to either go past the front wheel (limiting the steering) or over lots of power-sapping pulleys. The ZR has a clever solution - front wheel drive. With this, the chain run is short and only runs over one pulley on the important drive-side chain. The chain twists for steering, but the spring-loaded pulleys and tensioners mean that the front wheel can turn without problems. With no drive to the back wheel, back suspension is easy, and the single-sided swingarm makes it lighter... | 
