An interesting concept
That is an interesting idea, could lead to an effective two wheel drive system for motorbikes. Having a geared wheel like that does provide some potential engineering problems that will need solving. Not least any ingress of foreign materials, and there could be some efficiency concerns.
Also just occurred to me that a huge amount of the strength in a wheel is in the spokes (regardless of whether it is an alloy or proper spoked wheel), as a lot of the strength is guided from the rim through the spokes. The spokes provide both tension and compression strength depending on the position of the wheel. You loose that when you don’t have any spokes tethering the rim. It is extremely difficult to crush a proper spoked wheel, without it would have to rather massive to make up. Also it would have been be designed to prevent flexing in z axis to prevent warping of the wheel. That additional mass would increase the undamped mass and would have an significant impact on the design of the suspension system.
looks cool but how do you adjust the chain?!
Aside from looks, is there an advantage?
I suppose an effective electric two wheel drive system with regenerative braking.
Another disadvantage that just came to mind is lubrication of the rack and sprocket arrangement. It could potentially wear out rather quickly.
The concept has been around since 1989 and never works because they are so expensive to machine to tolerances. Basically the entire wheel is one big hub and as I know from replacing hubs on various cars over the years, the bigger the hub the more expensive it is.