The E-Spider achieves its lean through straight-up physics. The cockpit is suspended within the frame at points well above the driver’s center of mass. Rounding curves, that mass naturally swings outward, and a simple linkage causes the wheels to lean in the same direction, like two motorcycles riding side-by-side through a turn

http://www.bbc.com/autos/story/20150803-the-french-swincar-e-spider-is-the-worlds-most-amazing-atv