How often should a road bike chain be replaced?

[Simon]

It is recommended to replace it every 3-4 years. Timing Belt: The "timing belt" or "timing chain" is an important component of the engine. Function of the Timing Belt: The main function of the "timing belt" or "timing chain" is to drive the engine's valve train, ensuring that the engine's intake and exhaust valves open and close at the appropriate times to allow the engine's cylinders to properly intake and exhaust air. In some vehicle models, the timing belt also drives the water pump, such as in Volkswagen models like the Jetta EFI, Bora, Sagitar, and Audi.