What is the primary purpose of using a low gear in mountainous driving?

The primary purpose of using a low gear in mountainous driving is to maintain control and prevent brake overheating. When navigating steep grades, especially downhill, relying solely on the vehicle’s brakes can lead to brake fade due to overheating. By shifting into a low gear, the engine helps to slow the vehicle down through engine braking, allowing for better control without excessive reliance on the brakes. This not only helps to preserve the braking system but also enhances safety by reducing the risk of losing control due to brake failure in steep descents.

In contrast, using a low gear does not primarily aim to increase speed on downgrades or make gear shifting easier; these are not the main concerns when tackling mountains. While fuel economy can be a consideration in different driving scenarios, in the context of mountainous driving, maintaining control and safety takes precedence over fuel economy considerations.