5. Drivetrain Layouts

The final touch of how a vehicle puts the power on the ground includes various layouts. The car may accelerate using only the front tires, only the rear tires, both simultaneously, or both under various conditions. The most common setup for small cars and sedans is front wheel drive, meaning the front two tires are accelerated by the engine.

Sports cars, SUVs, and trucks typically use RWD. Having the rear tires accelerate is beneficial since the weight of the vehicle transfers to the rear tires under acceleration. Also, splitting the tasks of the front and rear tires allows for better overall traction.

Before moving on to 4WD, it is important to understand the Ackerman Principal, which explains how a car will turn ideally at low speeds:

Four wheel drive (4WD) has a huge advantage off road, on surfaces such as sand, dirt, ice, and snow, since all four wheels share the burden of accelerating the vehicle:

As promised in the previous video, understanding transfer cases can be tricky. This video should clear things up:

AWD vehicles are similar to 4WD vehicles, except most do not use locking differentials, and there is no low gear setting.

As mentioned above, locking differentials are common in 4WD vehicles, however open differentials or limited slip differentials are more common in AWD vehicles.

After understanding all the different ways power is transmitted to the ground, it is reasonable to be curious how steering is accomplished. Although there are numerous methods of steering, rack and pinion steering is very common, and is a simple solution to enable a car to change the direction the tires point.

In order to keep all four tires on the ground as much as possible, cars require suspensions. The next lesson will explain suspensions, and various form utilized in the automotive industry.

Lesson 6: Suspensions