How Will A Roof Rack Affect Your Car

Installing a set of roof racks to your car comes with multiple benefits but they do introduce some drawbacks due to the added wind resistance. Within this article, we discuss how a roof rack may affect your car and how to minimize the drawbacks.

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Whether you are transporting your bike or taking your old sofa to a recycling centre, installing a roof rack to your car is a great way to make it more practical. They are available in all shapes and sizes and they can be installed to most standard cars. However, after you’ve fitted them, you may notice that the roof rack affects your car due to the added wind resistance they produce. Below we discuss the main effects of using roof racks and how to minimize any drawbacks.

The Effects of Using Roof Racks


1. Reduced Fuel Economy

The main complaint that most people have when using roof racks is the fact that it reduces your car’s fuel economy. This is due to the fact that a roof rack increases your car’s wind resistance whilst driving. If this is a major concern, you can opt for an aerodynamic set of roof bars in order to reduce the loss in fuel economy.

2. Increased Wind Noise

Another way a roof rack affects your car is the added noise that comes in the form of a whistle. The faster that you drive, the louder the noise becomes and it can be very irritating on long drives. As mentioned above, an aerodynamic set of roof bars that cuts through the wind will help to reduce the whistle but it may still remain. If the noise is unbearable, you may even want to invest into a wind deflector for your roof racks.

3. Handling & Performance

Adding roof racks along with heavy loads such as a fully loaded roof box can certainly affect your car’s performance. The added weight along with the extra drag can worsen the handling and cause your car to experience more movements in high winds. However, depending upon the load you are carrying along with the type of car you drive will determine the severity of the handling and performance. For example, a large Mercedes GLS carrying a bike roof rack may not even notice a thing whereas a Volkswagen Polo carrying a heavy load will certainly feel the effects.

4. Height Restrictions

As soon as you install a set of roof racks, you’ll instantly increase your car’s overall height. Although the increase is only minor, it may be enough to cause problems whilst entering car parks or other restricted height areas.

5. Potential Damage

Depending upon the type of roof racks you install, there may be some markings left behind upon the rails that the racks clamp on to. Although the damage may be minor, it’s still something to keep in mind. In order to reduce any potential damage, many premium roof racks feature padded clamps to prevent any markings. However, if you do notice any markings, you may be able to use a car polish to rectify the issue or alternatively use a black trim restorer if the rails are plastic.


Choosing A More Aerodynamic Roof Rack

The ability of your roof racks to cut through the wind will determine how the roof racks will affect your car. As mentioned above, opting for an aerodynamic pair of roof bars can make a huge difference. They are primarily designed to cut through the wind with minimal resistance and you’ll certainly notice the difference.

As you can see in the below image, these roof racks aren’t designed to be aerodynamic and they are a budget set for occasional use around town. However, if we take this car out on the motorway, the whistling noise is very loud. This is because the square shape of the roof racks have no aerodynamic qualities whatsoever.

Effects of Using Roof Racks

Our other car that’s used for long journeys and has roof racks installed uses a more aerodynamic set. As you can see in the image below, the Thule roof racks installed have been designed to disturb the airflow with a more aerodynamic shape in order to reduce wind noise and improve fuel economy. We have certainly seen a difference since using them and the savings made from the improved fuel economy alone after thousands of miles travelled with them installed has probably paid for them multiple times over.

how will a roof rack affect your car's performance

It’s important to note that the aerodynamics between the racks is only really noticeable whilst driving without anything loaded on top of them. For example, if both of the racks above had a heavy car roof bag loaded onto the roof, the aerodynamics would mostly be reduced by the bag and not the roof racks.

Conclusion

Installing a roof rack to your car comes with so many benefits and the side effects that they have (as discussed above) are very minor. If you intend to leave the roof racks installed all the time, we strongly recommend that you invest into a high quality set to avoid disappointment. For the added investment, they’ll be more aerodynamic and probably come with added features too. If you are yet to install roof racks, we created a tutorial that walks you through the process.

author dan 4car

Written By Dan

Dan has been a car enthusiast ever since he can remember and has an extensive range of cars that include classic cars that he has restored himself from a barn find condition to modern performance cars. Whether you need advice on how to install car parts or recommendations on what products to buy, Dan’s first-hand experience will certainly help.

If you want to find out more about Dan, our testing process or the website itself, visit our about page for further information.

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