A misaligned rear axle causes reduced fuel economy. Caster and toe are the two possible adjustments to be made on a rear axle. Heavy outer shoulder wear on a rear tire indicates possible excessive positive camber. Recently the automotive service industry has focused on rear axle alignment. Some older technicians view this recent shift as a manufacturer's ploy to sell more equipment.
Some consumers resist rear wheel adjustment due to additional costs.
They see this as unnecessary since former cars did not need rear axle alignments. For front wheel drive and all cars with independent rear suspensions, proper rear axle alignment is necessary for optimum fuel economy and tire wear. Proper rear axle alignment makes the car drive better. Camber and toe are the rear axle adjustments. There is no caster setting for rear axles.