Carbon Fiber vs. Steel Car Bonnets

Fibreglass Bonnet

A car bonnet is a hinged cover that sits over the engine compartment of a car. Its main job is to protect the engine and other components from damage caused by road debris like rocks, dirt, and stuff. The bonnet also helps to reduce noise and vibration from the engine. Most car bonnets open from the front of the vehicle, either with a release lever inside the car or a key outside. Once it is open, you can get at the engine and other bits for checks, maintenance, and repairs.

The car bonnet isn’t just functional, though – it can also make a big difference to the look of a car. Many car makers add unique designs and styling touches to their bonnets to create a distinctive appearance. Car bonnets can be made from steel, aluminium, and carbon fibre. Each material has strengths and weaknesses, and choosing one depends on weight, strength, durability, and cost. Now let’s compare the two most popular car bonnet materials in the market, carbon fibre and steel. 



The weight of a car bonnet can have a significant impact on the performance of the vehicle. A lighter bonnet will help improve fuel efficiency, acceleration, and handling. Carbon fibre is an incredibly lightweight material, with a density of around 1.5 grams per cubic centimetre. In comparison, steel has a density of approximately 7.8 grams per cubic centimetre. This means that a carbon fibre bonnet will be significantly lighter than a steel one, which can lead to better overall vehicle performance.


Steel is known for its strength and durability. It is a tough material that can withstand much wear and tear. However, carbon fibre can be engineered as strong as steel, if not stronger. Carbon fibre is made up of thousands of tiny strands of carbon fibre that are woven together and then infused with resin. This composite material is solid and can withstand impacts without cracking or denting. Carbon fibre is more resistant to wear and tear than steel, which can withstand repeated stress and strain without degrading over time.


Carbon fibre is more expensive than steel. The manufacturing process for carbon fibre involves weaving together thousands of carbon fibre strands and then applying resin layers to create a composite material. This process is time-consuming and complex, which drives up the cost of the final product. In contrast, steel is a more explicit material to work with and is generally less expensive.


Carbon fibre has a distinct, high-tech appearance that many people find appealing. It has a sleek, modern look that is associated with high-performance vehicles. On the other hand, steel has a more traditional, classic appearance. It can be polished or painted to create a shiny, glossy finish, but it does not have the same high-tech look as carbon fibre.

Overall, the car bonnet is an important part of any vehicle, keeping the engine safe and letting you get at it when necessary. Its design, material, and appearance can affect the car’s performance and appearance.