Getting a lift kit for your truck is almost a rite of passage for all truck modding enthusiasts. However, despite the amazing change to the looks of the truck, lifting your truck will also make some not as amazing changes to the fuel economy of the truck.
When a truck is lifted, even by three inches, it becomes less aerodynamic; and as more air is allowed underneath the carriage, drag, and turbulence on the truck increases. Additionally, the lift kit adds weight to the truck. These factors affect and lower the gas mileage of the lifted truck.
Lifted trucks are just not as fuel-efficient as their stock, or even leveled, counterparts. Depending on the height of the lift, though, the difference in fuel economy might not be low enough to make that much of a difference.
How Much Will a 3 Inch Lift Affect Gas Mileage?
It’s fairly well known that adding weight and changing the aerodynamics of a vehicle will affect its fuel economy. The same is true when you level or lift a truck. Lifting a truck changes the aerodynamics of the truck, often adds significant weight to the vehicle, and changes the weight distribution of the vehicle, all, in turn, lowering the effective gas mileage of the lifted truck.
However, despite all that, the difference in gas mileage between stock and the same truck with a 3-inch lift may not be as drastic as you might think. Many people, myself included, reported that with a truck with the only modification being a 3-inch lift, the new gas mileage was only around 1 to 2 miles per gallon less if that.
With that being said, don’t be surprised to see a more significant difference between a stock truck and a truck lifted higher than 3 inches, as the hardware required to do so weighs more and adds more drag to the vehicle.
So that you can better understand the changes that happen to your truck after lifting it, we’ll be looking at the factors that affect your fuel economy:
- And other, smaller factors
When installing a lift kit in a truck, there are a couple things that happen:
First, the truck is lifted higher into the air.
Lifting the truck higher into the air increases the amount of air that is able to flow underneath the truck, increasing drag, and changes the weight distribution of the truck, making it more top-heavy. Those two things combine to make it harder for the truck’s engine to be able to push the vehicle in the ways it needs to, expending more energy and fuel.
Secondly, the truck is leveled out.
A lift kit is similar to a leveling kit in that it will level the truck out, but different than a leveling kit in that it also lifts the truck higher off of the ground.
A stock truck’s cab is lower than its bed. When a truck is made level, the cab is raised to be level with the bed. This raising of the cab messes with the aerodynamics of the truck. Before, the truck was angled slightly downward, offering a more aerodynamic and fuel-efficient stance.
After leveling, the nose of the truck is faced directly into the wind, largely increasing the drag experienced by the truck.
When combining these two things together, it increases the work the engine has to do to maintain speed and accelerate.
Weight plays a big role in the fuel economy of vehicles.
The lighter the vehicle, the easier it is for the engine to exert force on it and cause it to accelerate or maintain speed. The heavier the vehicle, the harder it is for the engine, as it has more weight to pull. This is why having lots of passengers or towing lowers your gas mileage.
A lifted truck has had some additional hardware attached to the undercarriage. Some suspension lift kits can add a significant amount of weight to the truck.
Also, as mentioned with the aerodynamics, the lift in the truck changes the weight distribution and the center of mass. Before the lift, the center of mass was lower to the ground, which made it easier for the engine to move it. As you lift a truck, the center of mass goes with it and makes it increasingly harder for the engine the higher the center of mass is.
While weight and aerodynamics are two of the factors with the biggest impact on fuel economy, they aren’t the only factors.
Should you tow a lot with your truck, naturally the added weight of the trailer is going to affect the gas mileage of the truck, lifted or not. However, towing tends to affect the gas mileage of a lifted truck slightly more than a stock truck, so keep that in mind.
Another factor will be the tires you use. A lot of people get bigger tires after lifting their truck. In fact, some people lift the truck specifically to use bigger tires.
Bigger tires do in fact affect the gas mileage of your truck. The bigger the tire, the heavier it is.
Also, larger tires have larger diameters and more of the tire touches the ground, resulting in more resistance and friction from the ground itself, causing the engine to have to work harder.
Will a Bigger Lift Have a Bigger Impact?
While a 2 or 3 inch lift won’t have a super big effect on a truck’s fuel economy, a 4 inch or greater lift will.
The bigger the lift, the more that has to be done to the truck. In the case of a 2-inch lift, and even sometimes a 3-inch lift, all that needs to be done is change the torsion bar keys and add a couple of blocks of aluminum under the leaf springs. Most of the time, this will be anywhere from a 5 to 10-pound addition of weight; a basically negligible increase in weight.
However, when lifting the truck more than that, significant work has to be done on the suspension system and the rest of the undercarriage. All this work and the addition of the new parts add some fairly significant weight to the system, increasing the demand for the engine and the impact on the gas mileage.
How Can I Improve Gas Mileage on a Lifted Truck?
Don’t worry, though, after lifting a truck it isn’t all doom and gloom, and fill your truck up with gas every other day. Fortunately, the gas mileage of a lifted truck can be improved.
One of the simplest ways to improve your gas mileage is to make sure your truck’s tire pressure is on point. Even just a slight variation in tire pressure can cause a drop in gas mileage, and with lifted trucks, we need all the help we can get.
Another solution is to upgrade some of the parts of your truck. Adding a performance exhaust, a new programming chip, or an air intake will all improve the performance and efficiency of the truck.
In the video below by YouTube channel Town & Country TV, they go over what happens to gas mileage after lifting a truck and how the performance exhaust they added helped their lifted truck actually get better gas mileage than it had gotten before! Do keep in mind, however, that if they had added the performance exhaust to the stock truck, the stock truck would have beat the lifted truck for fuel economy.
With all that said, one of the more complex, yet potentially most effective, methods to improve your gas mileage is to change your gear ratio. While the changes mentioned beforehand would work on a stock truck as well, changing the gear ratio wouldn’t work well, if at all, on a stock truck.
Receiving the biggest benefit from re-gearing the truck also requires you to have put bigger tires on your lifted truck.
Briefly, the gears that help to turn the tires are adjusted for the stock equipment in a stock truck. When you go in and mess around with the equipment in the truck, adding new tires and messing with the suspension, the gears have to turn more in order to push the tires the same amount as before.
By increasing the gear ratio of the gears in your truck, or the size of the individual gears, you can mitigate this issue. However, regearing a truck is an extremely complicated thing to do, and most certainly requires a professional.
I do not recommend you try and regear your own truck. Take it to a professional that is good at regearing trucks, and watch your truck get the best gas mileage it’s gotten since it was lifted.
Lifting a truck has many benefits, namely for the way it makes the truck look. Don’t let the downsides of lifting a truck scare you; many can be circumvented. While a truck with a 3-inch lift may need to be filled up slightly more often than a stock truck, it’s certainly worth the extra gas.