What does vehicle departure angle mean?
2 Answers
Vehicle departure angle refers to the angle between the tangent line drawn from the rearmost protruding point of the vehicle to the rear wheels and the road surface when the vehicle is fully loaded and stationary. In other words, it is the maximum angle between the horizontal plane and the plane tangent to the outer edge of the rearmost wheel's tire. Any rigid component fixed to the vehicle behind the rearmost wheel must not extend below this plane. The departure angle is applicable when descending a slope. As the vehicle moves downhill, when the front wheels have already reached level ground while the rear wheels are still on the slope, whether the rear bumper will get stuck on the slope depends on the departure angle. A larger departure angle allows the vehicle to descend steeper slopes without worrying about the rear bumper getting stuck and immobilized.
The departure angle is quite important for our daily driving, especially for those who frequently drive on mountain roads or navigate steep slopes. Simply put, it's the angle formed between the tangent line from the outer edge of the rear wheel to the lowest point at the rear of the vehicle and the ground when the car is fully loaded and parked on a flat surface. The larger this angle, the better, as it means the rear of the car is less likely to scrape the slope when leaving a steep incline. I learned this the hard way when driving a sedan up and down steep slopes—the rear bumper got scratched and lost its paint. Later, after switching to an SUV, I realized the departure angle was much larger, significantly improving off-road capability. It's a sibling parameter to the approach angle; the approach angle deals with the front of the car going downhill, while the departure angle handles the rear going uphill. Additionally, ground clearance also affects actual performance, so it's important to consider these parameters comprehensively when choosing or modifying a vehicle.
