The primary focus of functionality of the Raptor is it's off-road capability.
It has longer control arms that allows greater suspension travel.
The tire of most any car is an integral component of its suspension.
The greater the amount of rubber between the rim of the wheel and the road, the greater its component of the suspension.
The 17" wheel is the smallest wheel that will accommodate the disc brake on the Raptor.
And without some suspension work, like a lift, or some wheel well modification, the 35" diameter tire is the largest tire that will work properly on a Raptor.
Remember that a lift compromises your Raptors suspension optimization for off-road speed. So, most would not recommend that route.
My suggestion: Stay with 17" wheels with at least 0 offset and 35" diameter tires.
I went with 17" Method Standard 0 offset wheels and Nitto Trail Grappler tires.