How the Differential Adds Stability to Your Ride

If you've ever gotten your car stuck in the mud or snow you've probably noticed one wheel spinning while one stayed put. This may have caused you to wonder how this was possible. Today, we'll explain how the gear differential works to keep you on the road.

When two wheels are fixed to an axle and not allowed to spin independently, one of the wheels will have to slip during turns. This obviously can create a dangerous handling problem. Lucky for you, early auto engineers solved this problem with the gear differential. This little device sits in the center of your axel and allows the wheels to be turned independently.

Though it looks complicated, this device is quite simple but brilliant at the same time. In today's cars, each wheel is affixed to a separate "half axle" and supported by the frame which allows the wheels to turn independently at different speeds. Between these two "half axles" lies the gear differential. Simply put, this gear system consists of at least 4 angled gears, two horizontal and two vertical. The vertical gears are powered by the drive shaft and give power to the horizontal gears which are affixed to the two axles. This creates a steady stream of power and independent operation of the wheels.

Over the years auto engineers have worked to make these systems more efficient, more compact, and allowed them to deliver more power to the wheels. The first breakthrough here was solving the problem of keeping the car low to the road while leaving room for passengers. In the 1930's engineers knew they couldn't have a drive shaft running along the top of the floor in between the passengers. They also knew they couldn't shift the floor and roof absurdly high off the road to make room for the drive shaft. To solve this problem, the contact point between the drive shaft and gear differential was lowered and angled gears were used to keep constant contact and consistent power. This change made the whole system more efficient and much safer.