[Big Dave]

Pickup truck guys try this all the time and invariably it backfires and they get WORSE MPG, even after speedo error is corrected for.

Wheel/tire assemblies are flywheels. The rotational moment of inertia goes up with the square of radius.

Everytime you accelerate away from a stop (even if you accelerate very gently) you have to pour energy into those flywheels in order to spin them up. Guess where that energy comes from?

This is why vehicles with bigger wheel/tire diameter tend to eat brakes.

If you could drive without ever starting or stopping, accelerating or decelerating bigger tires would help, but that ain't the real world.

Maybe we need a sticky to address this evergreen fallacy.


Empirical data shows thar gearing works and bigger tires are counterproductive.