Hubless Wheels?!

In a so-called 'hubless' wheel, the hub is actually a large thin ring that fits just inside the rim of a large bearing with the tyre on its outside. The inner ring itself attaches to the vehicle's frame. On a motorbike, the front wheel also has to handle the steering.

link: http://www.sciencefocus.com/qa/how-do-hubless-wheels-work