What is the beam under the car door called?
4 Answers
The horizontal bar under the car door is called the side skirt or lower bumper skirt. Here are the specific details about car side skirts: 1. Material: The lower bumper skirt is made of ABS engineering plastic, while aftermarket large/small body kits and skirts generally use ordinary plastic or fiberglass. 2. Function: The side skirt refers to the skirt panels installed on both sides of the vehicle body, serving the same purpose as an air dam by reducing airflow entering under the vehicle. It has certain aerodynamic effects and can significantly reduce air resistance under specific conditions. Proper installation can minimize reverse airflow generated during vehicle operation.
In our industry, we usually call it the rocker panel. It's located right below the car door and is part of the vehicle's overall structure. Don't underestimate this crossbeam - during side impact collisions, it deforms to absorb impact energy and protects passengers in the cabin from being crushed. Safety performance largely depends on it. My previous car's rocker panel helped cushion the impact during a minor collision, preventing more serious damage. They're typically made of high-strength steel or aluminum alloy, and many new cars now add fillers inside for reinforcement. If you often drive on bumpy roads, be sure to check for deformation or rust, otherwise the vehicle's stability will be significantly compromised. Replacement can be expensive, so when parking daily, avoid getting too close to roadside curbs. Prevention is key, as driving safety should always come first. This ingeniously designed beam is crucial for your family's safety.
The horizontal beam under the door is called the sill beam, and I've encountered issues with it on my car. Last time after washing the car, I noticed a strange noise when closing the door. Upon inspection, I found some gravel stuck in the sill beam area. After a simple cleaning, it improved significantly. This area is most prone to being stepped on when loading passengers or heavy items. If the material isn't durable enough, long-term wear can lead to rust. I recommend regularly pressure washing this area, especially in northern regions where road salt can accelerate corrosion. By the way, driving over too many potholes may also cause slight deformation of the sill beam, affecting door operation. From my experience, it's worth having a professional inspect the car body every six months - a small investment for peace of mind. Remember not to modify this area without professional help; even adding running boards requires proper installation to avoid compromising structural safety.
The sill beam is that structural component, which is quite interesting in vehicle body design. Older cars used regular steel, but now they've upgraded to high-strength alloys, making it lighter yet stronger. This change has significantly improved crash test performance, and it also supports the underbody frame, enhancing overall stability. At high speeds, the body would wobble noticeably without it. Material advancements have also contributed to better fuel efficiency. In daily use, if a door doesn't close properly, it's likely the sill beam has been slightly bent. During repairs, always check here for dents or cracks first.
