Why helical gears are more favourable in vehicle transmission than straight -cut spur gears?

Helical gears are more favorable in vehicle transmission than straight-cut spur gears primarily due to their ability to engage gradually, which results in smoother and quieter operation. Their angled teeth allow for a larger contact area, reducing stress and wear, thereby enhancing durability and efficiency. Additionally, helical gears can handle higher loads and provide better performance at higher speeds compared to straight-cut spur gears. This makes them ideal for applications where smoothness and reliability are critical, such as in vehicle transmissions.