Reduced traction results in tire slippage, a source of energy loss. Condition of balanced and unbalanced tires and road contact. Loss of fuel economy may range from minimal to considerable, depending on the degree of tire imbalance and the vehicle's operational speed. The greater the imbalance and the greater the speed, the greater the loss of traction and a corresponding loss of fuel economy. Improperly balanced non-driving wheels affects only ride and tire life.
Unbalanced tires exhibit a spotty, erratic, cupped wear pattern.
Force dynamics create this wear pattern. Energy is lost scuffing away the rubber. See Figure 2 for tire wear pattern. Figure 2 Illustration courtesy of Moog Automotive. Tire life impacts energy reserves since crude oil is a raw material used to produce tires.