Why do some drivers spend thousands of pounds improving their car wheels? Is it about looks or is there a technical reason behind it? And how do different size wheels affect the way you drive your car?

The wheels on your car have a tough job. As well as transferring power from the engine to the road and directing it in the direction you’d like to go (along with the four tires wrapped around them), the wheels must maintain their perfectly round shape to give you a smooth ride. , despite having bounced off speed bumps, through potholes and crushed against curbs during poorly judged parking maneuvers. In many cars, especially high-performance models, they can also help cool the brakes to make sure the car comes to a safe stop when driving hard. So how do different wheels affect the way you drive your car?

Lower-priced new cars, and many older cars, will come standard with steel wheels. Steel is the metal of choice for most parts of a car, as it is cheap and can be manufactured in different shapes quite easily, which is why it has always been an obvious choice for wheels. But more and more cars are equipped with wheels made from aluminum alloys, which are stronger and lighter than steel. An alloy wheel will be much lighter than a steel wheel of the same size, which improves the handling and handling of the car, as there is less weight rebounding for the suspension to support it and less weight for you to steer when you turn the wheel. steering wheel. An alloy wheel is also stronger than a steel one, which means it will flex less in the corners, which will help the car handle better. However, a very large impact (such as hitting a pothole) is more likely to break or break an alloy wheel, whereas a steel wheel will flex and absorb some of the impact, making it less likely to break.

Alloy wheels also tend to be sleek and polished, while steel wheels rust unless treated and painted, and are usually covered in a decorative plastic trim (you know, the kind you inevitably see lying on the side. off the road after they fall off), which is why a set of alloy wheels usually improves the look of a car.

Most cars will give you the option of paying more money to install larger alloy wheels. In the car, however, the overall rolling height of the wheel and tire must remain the same, so a larger wheel means a lower profile (thinner) tire. In the photo to the left we have a 15-inch rim (left), a 16-inch rim (center), and a 17-inch rim (right), all mounted on rims to fit the same car. If you look at all three wheels, you will see that the overall height of each wheel / tire unit is the same, but the 17-inch wheel has a much ‘thinner’ rim than the 15-inch wheel.

Being made of rubber, the tire flexes and absorbs much of the small impact from bumps in the road, effectively forming part of the car’s suspension. A lower profile tire has less rubber on the sidewall to flex and absorb bumps, so a larger tire and thinner tire combination will give you a firmer ride, making the car feel noticeably more bumpy. However, less flex and oscillation will mean better handling as the car changes direction around a curve or when braking.

But the real, simple reason most people pay a lot of money for bigger tires is for looks, although don’t expect expensive alloy wheels to add much to the car’s resale value down the road. I used to have an Audi A5 with 20-inch alloy wheels (the standard was 17-inches). The large wheels meant the tires were extremely low profile, so hitting a pothole or going over a speed bump was literally a painful experience and at times it felt like the car had no suspension at all. But it looked fantastic.