Do Roof Racks Affect Gas Mileage? Expert Answers

Yes, roof racks can negatively impact gas mileage due to increased aerodynamic drag, resulting in reduced fuel efficiency.

Do Roof Racks Affect Gas Mileage?

It’s inevitable that if you add an add-on to your vehicle, you will have to endure a significant impact. Since a roof rack is the most popular external gear for a car, many people use it to make the journey comfortable. However, using a roof rack also has its side effects.

Many people wonder whether a roof rack affects on car’s mileage. Unfortunately, the answer is yes. The reason is simple. A roof rack negatively impacts a car’s fuel economy, handling, etc. Besides, the higher center of gravity and enhanced areas are unveiled to wind from the front and backside.

However, there’s a difference in that matter. If you carry oversized and heavier items, it can reduce the mileage productively. The mileage performance won’t be so massive if you convey lighter items.

So, the question is, how does a roof rack impact on car’s gas mileage? To know about the topic thoroughly, read further –

Does a Roof Rack Affect a Vehicle’s Performance (Gas Mileage & Fuel Consumption)

There’s no question regarding the roof rack’s profound influence on a vehicle’s overall performance. Since it can significantly increase wind resistance, it impacts the vehicle’s performance. But the question is, how does a roof rack impact a vehicle’s performance? Well, I’ll answer it.

How Does a Roof Rack Affect a Car’s Mileage?

How Does a Roof Rack Affect a Cars Mileage

A roof rack can impact a car’s mileage in various ways. Firstly, if the rack is empty, it’ll create wind resistance and drag. As a result, gas mileage was reduced drastically. Secondly, if the rack conveys considerable weight, the gas mileage decreases vehemently.

The added weight will undoubtedly influence the car’s engine. Lastly, the car’s security will be at stake if the rack isn’t correctly secured.

I can give you a practical example of mine in such a case. Last year, my wife and I rode in Cape Town with our beloved Nightfall AWD. We had our Thule AeroBlade Edge Raised Rail Load Bar with us. It was full of various households and one piece of sports equipment.

The fuel economy drastically reduced when we started our journey with this roof rack. When we removed it, we saw that the fuel economy improved by 5 gallons. We did this fuel economy test in our 90-mph highway journey in Cape Town.

Nevertheless, I want to add one thing. It doesn’t mean which brand you’re using; almost all the roof racks will drag your fuel economy. It’s true.

During the long-term test of our 2022 Nightfall AWD, we were initially disappointed in our observed fuel economy. The reason is simple. The rack was full of heavier equipment.

Hence, we’ve decided to remove some gears from it. Then we’ve seen the fuel economy improve in the past. After a while, we opted to remove the rack to see how much of a difference it made.

Removal takes roughly 10 minutes. Upon removal, we instantly saw increased efficiency numbers, prompting us to make a second attempt at our 90-mph highway fuel economy test.

In the second run, we bested our prior attempt by 3 mpg (25 mpg to 28 mpg), a 12 percent increase and better than the EPA‘s highway figure of 26 mpg.

Even though the units fitted to our Carnival are shaped to be aero-friendly, they still take quite a toll on its ability to slice through the air. This uptick in drag increases exponentially as speeds rise so that around-town driving will result in a lesser hit to fuel economy than highway motoring.

Impact of Aerodynamic Force on Car’s Gas Mileage

Impact of Aerodynamic Force on Car's Gas Mileage

The aerodynamic forces also greatly impact a car’s gas mileage. The air resistance increased due to extra add-ons on the vehicle. Additionally, the resistance creates a high-level drag force and extensive pressure on the car’s engine.

For this reason, it has a negative influence on gas mileage.

Impact of an Empty Roof Rack on Gas Mileage

Impact of an Empty Roof Rack on Gas Mileage

Many people have a question on their mind – do an empty roof rack can affect gas mileage?

Unfortunately, the reality is, an empty roof rack can also make an impact on gas mileage. Yes, it might sound strange. I’m not carrying anything on my rack, so why will it affect fuel consumption? Solid question.

Actually, the aerodynamic shape of an empty roof rack is the main reason that leads to fuel consumption.

Impact of Vehicle Type on Gas Mileage

The impact of roof racks on gas mileage varies between different vehicle types. Usually, small type cars have to endure the bad influence of gas mileage due to the rack than the bigger cars, trucks, or SUVs. The shape and size of the vehicle play a role in understanding how much drag is created by the roof rack.

Does Snow Affect Gas Mileage?

Does Snow Affect Gas Mileage

Of course, snow affects a car’s gas mileage. My car is Kia Nightfall AWD. I often drive it 220 KM stretch of highway in Cape Town suburban. When I drove my SUV last winter, I understood this fact correctly. The snow-covered road can drastically increase the rolling resistance between the tires and the road surface.

As a result, my SUV needed more energy to overcome this situation. It significantly reduces fuel efficiency. So, it’s pretty much clear that snow effectively affects gas mileage.

How Can I Improve the Gas Mileage of Your Automobile Significantly?

To improve the gas mileage of the automobile, you could follow some tips –

  • Avoid rapid acceleration and heavy braking. These actions can consume a tremendous amount of fuel. Instead, accelerate slowly and maintain a steady and consistent speed when rolling around the street.
  • Underinflated tires can increase fuel consumption. Keep tabs on tire pressure regularly and ensure they’re inflated to the recommended level instructed in the vehicle’s manual.
  • Remove the added weight from the car. Hence, the car will be lighter and directly impact fuel economy.
  • You can purchase an OBD-II code reader and a car computer. You can use it to see trip gas mileage. It will give you feedback on each trip. So you can quickly see the impact of the changes.
  • When driving on highways, try to use cruise control. Cruise control can help you to maintain a steady speed and avoid unnecessary acceleration.

How Does Tire Pressure Affect the Fuel Economy?

Tire pressure lowly affects fuel economy. The impact of tire pressure isn’t that notable. Since it increases the vehicle’s rolling resistance, more power is needed to outplay the rolling resistance. It indicates more fuel is required. Hence, the tire pressure affects the fuel economy.

Does Wind Affect Gas Mileage?

It sounds a bit awkward. However, you can’t ignore it. The wind is capable of affecting the gas mileage of a vehicle. If you drive your car at a higher speed on the road, there’s a massive chance that wind will make an impact on fuel efficiency. Here’s the proof –

  • When driving at full speed on the road, your vehicle experience resistance from the air. This resistance is called aerodynamic drag. On the other hand, driving against a headwind creates extra resistance, which your car will face challenges to overcome. Lastly, a tailwind can decrease resistance and enhance fuel efficiency.
  • The impact of the wind on gas mileage will become more visible when you drive your car at the highest speed. The more speed you take, the wind will resist with more power. For example, driving at high speeds in powerful headwinds will influence a car’s gas mileage.

How Much Does a Roof Rack Affect Gas Mileage?

How Much Does a Roof Rack Affect Gas Mileage

According to car experts, a roof rack might reduce nearly 5 miles per gallon on a car’s mileage. Although it could differ in terms of cars, it’s an average amount. However, it is only applicable to empty roof racks. Things could be much worse if the rack is filled with heavier items.

The rack could reduce almost 12 gallons in such a scenario.

Do Roof Rack Kills MPG?

Roof and ski racks notably kill MPG (Miles Per Gallon). What do you think? Won’t these things have any side effects? Of course, they have! So, when you use them, you’ll have to face challenges. A roof rack productively cuts highway mileage and costs you more money.

Final Say

So, I can assume that you’ve learned how a roof rack affects a car’s gas mileage. Yes, a roof rack makes your journey convenient and necessary for sports goers. Notwithstanding, you have to consider its other sides too.

It’s necessary to know the negative impacts of roof racks. This is how you can correctly decide how to use the rack perfectly per your budget. Do you have anything to know about this article? If you have any questions, you can ask them in the box below. Thank you and goodbye!

Automotive products are like an addiction to me. Years ago, I started my job at a Roof Box installation co. Then I realized that I have a passion for cars. It is a perfect scope to share my different experiences about automotive products.