Does the install of a larger rim and tire size shorten the life span of your car's mechanical parts such as steering pumps axle bushing and joints?

Answer 1

The following are theoretical effects from installing larger wheels and tires on a vehicle:

--because the tires are slightly larger and cover more distance in one revolution, the engine will turn more slowly to achieve the same speed. This is generally GOOD for the engine, because of lower RPMs, and also for engine-driven accessories, such as steering pump, alternator, etc. There also could be a slightly improvement in gas mileage.

--if the tires are significantly larger, the speedometer will (usually) be less accurate and will tend to underestimate your speed (e.g. indicating 60 mph when you're really going 62).

--if the tires/wheels are HUGELY bigger, such as on a seriously offroading Jeep or a monster truck, their additional weight will be much harder on the engine, drive train and suspension components. This is because the engine, transmission and differential must work harder to rotate the heavy wheels. Huge wheels/tires also put more stress on the steering and suspension, whose springs and shock absorbers must manage the extra weight at the ends of the axles.

As a practical matter, though, a small increase in size will make little difference to other mechanical components. And most factory speedometers slightly overstate your speed (e.g. indicating 60 mph when you're only going 58), so slightly larger wheels/tires might make the speedometer more accurate, not less.