Most rear wheel wells are made of metal. Wheel wells are coated with a rock-proof, rubberized coating underneath to prevent the rocks kicked up by the wheels from damaging the metal and making a lot of noise when they hit. The front wheels are often made of plastic. This is because it is harder to mount the engine with the front wheel wells in place. Plastic wheel wells can be removed, and are easier to mount the engine during the manufacturing of the car.
Some wheels are a combination of the two.
Generally cast alloy wheels are higher priced, but have greater strength than stamped sheet metal wheels. The most common are the stamped sheet metal wheels because they are less expensive to produce and are adequate for most uses. Cast aluminum wheels are very popular, magnesium wheels are also popular. Both are popular because they are lightweight and strong. Windshield Most windshields are stationary.