Cars are quite tricky to design and build – if they weren’t, we’d all be driving around in the wheeled manifestation of our own imaginations. Manufacturers spend years developing and designing the right materials for their cars – but what are they?
Car-makers have to consider a range of factors when designing a car including weight, strength, perceived quality and ease of repair and construction. A car made of the most exotic materials might be incredibly strong and light, but it’ll cost a small fortune to produce. Manufacturers often need to use a mixture of materials in one car to achieve their goals.
With so many different types of materials on offer, however, keeping track of what’s what and why you’d choose it over any other option can be tricky. We’ve put together a simple list of all the materials you’re likely to find in a car and described their uses and strengths.
Plastic is never going to feel as good quality as a metal alternative but it’s likely to weigh a lot less and be cheaper and faster to produce and paint. Plastic is used on cheaper cars for external body panels like the bumpers, wings and sills. While you might be able to bend the panels with a stiff prod, plastic makes sense as body panel material as it’s light, resilient to impacts and easily replaced if damaged.
Most car interiors are predominantly plastic because it’s easier to mould into the complex shapes demanded by car buyers – ‘soft-touch’ plastics are popular in more expensive cars as they feel much more luxurious to the touch than regular plastic.
Unquestionably the most common material used in building cars. Steel is strong, easy to work with, cheap and readily available and almost every car will have some steel in it. It can be used for parts like the roof, chassis, wheels, brakes, exhaust and engine. It doesn’t take extremely specialised tools or knowledge to produce, manufacture and repair steel so is the cheapest metal used in car building.
Steel comes in a variety of different grades with lightness increasing in proportion with the cost of manufacturing the material and making the part. Manufacturers will often use more than one type of steel in a car – prioritising better steel where more reinforcement is needed.
Aluminium is the other common metal used in car manufacture. It’s much lighter and stronger than steel and, unlike its ferrous friend, isn’t susceptible to rust. It is, however, much more expensive and far harder to work with than steel so isn’t commonly used on cheaper cars. Jaguar and Audi are the two main manufacturers associated with aluminium-constructed cars.
It shot to fame through racing cars but was quickly usurped by carbon fibre as the wünder-material in vogue. Manufacturers like Ferrari aren’t convinced, however, saying they can shape an aluminium body panel easier than a carbon fibre one with only a negligible increase in weight.
With advanced metals on the one side and carbon fibre on the other, fibreglass has fallen out of popularity in the motoring world. Like carbon fibre it’s made by embedding small strands of glass in a mat then setting it in plastic. The combination of glass’ resilience and plastic’s flexibility means fibreglass is very lightweight, fairly strong and resistant to bending.
It’s not really used in mass production cars anymore and was only popular with the, now-dormant, sports car maker TVR and on early Chevrolet Corvettes for its lightweight. Its relative weakness compared to some metals and the complexity of repairing it means it’s now mainly used in maritime and aviation applications.
The fashionable material of choice for the automotive elite. Carbon can be used in numerous ways around a car but the most common is as carbon fibre. Like fibreglass, its small strands of carbon embedded into a fibrous mat and sealed by a plastic or resin. This ranges from mass-produced carbon fibre in the Alfa Romeo 4C’s chassis ‘tub’ to ludicrously-expensive hand-laid carbon fibre used mainly in F1 cars.
Carbon can also be mated with ceramic and used in car brake disks. In this form it’s not dissimilar to the heat-resistant tiles that protected the space shuttle on re-entry through the atmosphere. Carbon is multiple-times stronger and lighter than steel but also multiple-times more expensive so only features on the most expensive cars in the world.
Leather upholstery is a desirable option on many a higher-spec car. Leather is the prepared hide of an animal (usually cows) and its resilience to abrasion and staining means it works well as an interior material. The more leather you have – the more expensive your car will be as it takes that much longer than cloth to stitch and trim it.
Many manufacturers are, for a variety of ethical, practical and financial reasons, moving towards using artificial leather in their cars – for example, Mercedes‘ range of Artico leather seats.
Magnesium enjoyed popularity as a car building material in F1 in the 1970s and could potentially be making a comeback. It’s lighter and stronger than steel but is easier to work with than aluminium providing a good middle-ground between steel and carbon fibre. Unfortunately, its percieved propensity to burst into flames (remember GCSE chemistry?) meant that few have put real backing behind it.
Titanium is also used in certain high-end car parts, most commonly sports exhaust systems. Titanium has the highest strength of any metal for its density so, for car makers like Porsche, is helps reduce the cars weight and provides a tougher part.
Living in a material world…
Most manufacturers stick to the above materials but, with pressing environmental motivations, many are feeling obliged to look into different materials to reduce weight and thus fuel consumption of their cars. Most cars are built with a combination of materials and, like the Citroen C4 Cactus, it’s how materials are combined that makes the difference between a decent car and a great one.
As a general guide, touch everything in any new car you’re thinking of buying. Poke all the outside panels and interior materials and switchgear. Your finger is the best guide to whether you think something feels expensive or not so make sure you like what your car is built from before you buy it.
Now you’re clued in to the weird world of car materials why not take a look at our handy guides to other weird motoring terms like torque, horsepower and ABS or our explanations of car paint types or Euro NCAP safety scores.