Which gear is most likely to use a spur gear in a manual transmission?

In a manual transmission, reverse gear is most commonly associated with the use of spur gears. This is because spur gears are straightforward in design, being teeth cut straight across the wheel, allowing them to efficiently transmit force in one direction with minimal complexity.

When engaging reverse gear, the system needs to be both simple and robust since it handles the unique requirements of reversing the vehicle's direction. Spur gears are well-suited for this because they provide a direct engagement and are more compact, making them ideal for the space-limited environments of manual transmissions.

While other gears, like first or second, might also utilize different gear designs (such as helical gears), which can provide smoother operation and upwards in load capacities due to their angled teeth, reverse primarily relies on the straightforward nature of spur gearing. This design minimizes potential noise and enhances reliability when reversing the vehicle, making it the most practical choice.