Bill Yamnitz
Mulberry, FL

A: A motorcycle tire needs that curved shape in order to allow the various forces (well, accelerations, actually) of gravity and inertia to interact with the motorcycle’s chassis in a turn. Just like Mr. Hayden, pictured on the right. 

On a trike, there’s no need to create lean in order to turn, so why not utilize a flatter tire? It basically comes down to cost and availability. A typical motorcycle front rim requires a large-diameter, very narrow tire compared to any automotive application. And there simply aren’t many options for alternatives. Furthermore, most trikes rely upon motorcycle suspension systems, which are designed to work with the geometry and characteristics of motorcycle tires.

With the continual development of new trike-specific suspension systems, we may yet see a new front-end design, but until then, it’s simply easier to use what works. A common workaround is to mount a motorcycle rear tire of similar size as a front tire. A rear tire typically offers a slightly flatter profile and longer wear, making it a common trike option.

Legal eagle bit:
Of course, always consult your original trike kit manufacturer before making any changes that may affect the safety of your vehicle.