Originally Posted by gkirk
Stickier rubber means more traction = more friction = less mileage.
Bigger wheels = heavier (usually) and much worse rotational inertia since the weight in the wheel is further toward the edge = worse mileage.
Or in other words with bigger heavier wheels you have four flywheels
by definition at each corner. A flywheel being a device that is used to store
rotational energy. Just be gentle getting them up to speed and your fuel economy will be quite fine.