What is the name of the black semi-circular plastic above the tire?

[LeRowan]

The black semi-circular part above the tire is called the wheel arch or fender flare. Below are some related details: 1. Wheel Arch: It refers to the chrome trim along the upper edge of the tire, which is a semi-circular component protruding from the fender above the car tire. It is typically composed of 1/2 steel and 1/2 plastic, and this applies to both front and rear wheels. It is commonly referred to as the 'eyebrow' of the wheel, hence the name wheel arch. 2. Function of the Wheel Arch: The wheel arch helps prevent rainwater and gravel from being splashed onto the car body by the rotating tires, thereby protecting the paint. Generally, the wheel arch of factory-installed cars is slightly wider than the tire. However, this does not apply to modified cars, as they often use wider wheels that align with the wheel arch for aesthetic purposes.

[MacTanner]

When driving, I often notice that black semi-circular plastic component above the tires, commonly referred to in the automotive world as the wheel arch liner. Its primary function is to shield the inner wheel arch, preventing mud, water, and gravel from splashing into the engine bay or underbody components. Think about driving through puddles on rainy days or rough roads—it silently protects the car body from corrosion and potential short circuits. From my experience, these liners are typically made of ABS plastic or reinforced composite materials, designed with some flexibility for easier installation but prone to aging and cracking. If you frequently drive at high speeds, strong winds can loosen them; off-road enthusiasts should especially check the bolts regularly to ensure they're tight, otherwise accumulated mud can cause them to fall off. Replacement isn’t expensive, costing just a few dozen bucks at an auto repair shop. If you DIY, you’ll need to remove the tire and wheel arch trim—just make sure to pick the right model-specific part to avoid mistakes.

[MelanieLynn]

As an automotive maintenance enthusiast, the first detail I check on every vehicle inspection is the condition of the wheel arch liners. This component is standardly referred to in the industry as the fender liner, positioned above the wheel arch curve, with its core functions being noise insulation, vibration damping, and contamination protection. It is mostly made of black thermoplastic material, economical and practical but with average weather resistance. I've encountered numerous cases where owners' liners were damaged—for instance, prolonged accumulation of mud at the lower part leading to cracks, allowing rainwater to seep in and rust the frame; or high-speed impacts from stones easily causing perforations. Maintenance advice includes using a high-pressure water jet to clean the back of the liner during quarterly car washes to remove trapped branches and debris; during installation, ensure the clips are properly aligned to avoid rattling noises. If wider tires are installed, extended liners must be used to match the wheel arches; otherwise, it could affect heat dissipation and safety. Replacement parts are readily available from branded suppliers on Taobao.

[SavannahLee]

When I first bought the car, I was also curious about that black plastic semicircle above the tires. After asking a car-savvy friend, I learned it's called a wheel arch liner—basically an inner fender shield designed to prevent dirty water from splashing around. It protects the area under the hood from rust when driving in the rain. Once, while driving on a muddy rural road, it got caked with dirt, which only got cleaned off during a car wash. For routine maintenance, just clean it regularly to prevent debris buildup, which can cause odors and shorten the car's lifespan. As a newbie, I find it practical but definitely not something to overlook during checks.

[Gemma]

When discussing car care, I must mention the importance of wheel arch liners. The function of this wheel arch liner is to seal and isolate debris from entering the body cavity. The material is commonly PVC plastic, which is lightweight but brittle. If damaged, rainwater leakage may corrode wires or cause mold and odors. It is recommended to visually inspect for cracks once a month; during car washing, carefully wipe to avoid residue of corrosive agents. When installing a new liner, ensure the size matches the original factory specifications, otherwise, high-speed driving wind pressure may cause detachment. From a maintenance perspective, applying UV-resistant spray appropriately can extend its lifespan, especially in rainy southern regions. Seasonal cleaning of snow and salt is also crucial to prevent chemical erosion from accelerating aging.

[LandonRose]

From a safety perspective, the black curved plastic piece beside the tire is indeed the core protective component of the wheel arch liner. It prevents high-speed flying stones from causing injuries or water ingress leading to short circuits in components. For instance, on rainy road surfaces, it significantly reduces the risk of water splash entering the brake system. My experience is that if the liner falls off or cracks, increased noise can distract driving focus, and even cause higher skid risks when water accumulates. Regular inspection of fasteners is essential, especially checking screw tightness after driving on bumpy roads. During maintenance, prioritize flexible material liners for better impact resistance, ensuring overall vehicle safety and smooth operation.