DrewE wrote:
Everything else being equal, a wider tire will reduce gas mileage, not increase it; the wider tire has greater rolling resistance (and greater traction due to a larger contact patch), and also a greater rotational inertia that takes more energy to speed up and slow down. For smallish changes in tire size, the differences are small, and other factors can also come into play such as the composition of the rubber and often the overall diameter of the tire.
There are good reasons why you don't see anything other than skinny tires on Tour de France bicycles.
Hmmmm .... most likely a larger contact patch area carrying a given amount of weight as compared to a smaller contact patch area should have worse traction on a road surface.
The larger contact area will have less pounds per square inch of contact area pressing down against the road surface - hence each square inch should provide less lateral holding force from friction with the road surface.
I believe narrow tread areas (for any given weight) do better on slippery surfaces than wide tread areas (for any given weight) because the greater pounds per square inch of narrow treads means they can "punch through" to a hard surface. Of course wide tread areas due better at not getting stuck on soft surfaces because less pounds per square inch means thay can float weight up higher on soft stuff.
I once had a Mustang that I retrofitted with big ole' wide tires. In general it handled terrible with the wide tires - but it sure "looked good"!