What is the main function of a serpentine belt?

The main function of a serpentine belt is to drive multiple accessories in a vehicle's engine by using a single continuous belt design. While it can indeed drive on both sides of the belt, this feature is primarily utilized in space-constrained environments where multiple components need to be powered efficiently. The serpentine belt wraps around various pulleys and can operate several devices such as the alternator, power steering pump, water pump, and air conditioning compressor.

This design allows it to provide power to these accessories with reduced complexity and weight compared to multiple belts. The versatility of the serpentine belt in driving components from both sides maximizes functionality while minimizing space and parts involved in the system.

In context, other options relate to different characteristics of power transmission systems. Driving at low speed applies to specific types of drives that may not use a serpentine belt. Increasing the area of contact could refer to improving grip or friction in various applications, but it is not the primary function of a serpentine belt. Self-tracking on sheaves indicates a design feature related to belt alignment but does not cover the core purpose of power transmission provided by the serpentine belt.