Fit For BMW 3 series G12 G38 Auto Brake Discs Size 348 374 395MM 

Specification of BMW Auto Brake Discs 

The working principle of car brake discs

The working principle of a car brake disc is to generate resistance through friction to decelerate or stop the vehicle. The brake disc is typically used in conjunction with brake calipers and brake pads. When the brake pedal is pressed, the brake pads on the caliper are pushed against the brake disc, creating friction. The resulting frictional force provides the resistance needed to decelerate or stop the rotation of the wheels.

The brake disc needs to be replaced in the following situations:

1. Brake disc wear: The brake disc wears over time and usage, and when its thickness is below the manufacturer's specified minimum thickness, it needs to be replaced.
2. Brake disc deformation: Excessive heat expansion and cooling can cause the brake disc to deform. When the brake disc exhibits noticeable waves or indentations, it needs to be replaced.
3. Brake disc cracks: Excessive impact or fatigue can lead to cracks in the brake disc. If the cracks exceed the manufacturer's specified safety limits, the brake disc needs to be replaced.

Brake discs on the market are made of materials such as carbon steel, cast iron, and steel-reinforced composite materials. Different materials have different characteristics and performance. Carbon steel brake discs have good wear resistance and heat dissipation, but they are expensive. Cast iron brake discs are relatively economical but heavier and have poorer heat dissipation. Steel-reinforced composite material brake discs are lightweight and have good heat dissipation, but they are more expensive.