How Much MPG Will I Lose With Bigger Tires?

Upgrading your tires to larger ones is a great way to make your offroading adventures more exciting.

But with gas prices as high as they are, it’s important to consider that you will lose fuel efficiency with larger tires.

The question, then, is: how much MPG will you lose with those larger tires?

How Much MPG Will I Lose With Bigger Tires?

The exact MPG that you’ll lose with bigger tires depends on your vehicle, tread, the width of your tires, if you add a lift kit, and how many sizes you go up. The loss of fuel efficiency with larger tires could range anywhere from 2-25 percent of your current MPG.

However, if you’re only going up a size or two in diameter, you are liable to see an increase of one to two miles per gallon at the most. 

On the other hand, if you’re fixing to go up several sizes in diameter and width, with multiple inches of lift and aggressively treaded tires, your miles per gallon will most likely decrease significantly.

It can be as much as five to six miles per gallon.

To learn more about the reasons you’d switch to larger tires and how tire size can affect your mileage, continue reading.

What Is MPG?

Miles per gallon or MPG refers to the distance in miles a vehicle can travel per gallon of fuel. 

Moreover, MPG is also the best indication of fuel efficiency. 

The higher a vehicle’s MPG, the more fuel-efficient it is, and likewise, a low MPG indicates a fuel-inefficient car.

If you’re looking for a vehicle with good MPG, look for a car that gets anywhere between 50 and 60 MPG. 

These numbers demonstrate that the car is both economical and efficient and translate to low car tax rates and running costs. 

However, adding larger tires to your vehicle can change that number by 1-6 miles per gallon.

Why Put Bigger Tires on Your Car?

This decision can be a bit more complicated than you’d expect. Some people want bigger tires to go off-roading. 

Other people want bigger tires for performance and speed or just for their aesthetic appeal. 

However, because our vehicles are used to get from point A to point B, you must consider other factors when shopping for new tires.

Generally speaking, bigger tires on a car will decrease its fuel economy since the tires are heavier and require more power from the engine to move them. 

Ultimately, gas mileage depends on tread, width, diameter, and other factors.

How Can Bigger Tires Affect Mileage?

Placing a bigger tire on a car will decrease its MPG in virtually every situation.

This has to do with the fact that they have a larger surface area which creates more resistance between the car and the ground. 

Furthermore, the more considerable weight of the tire causes the engine to work harder when rotating the bigger tires.

Rolling Resistance

Rolling resistance describes the force exerted on your tire as it moves on the ground. It’s an intricate subject that requires lots of physics and math to understand comprehensively. 

However, by tying all the following factors together to create a smooth working system, you’ll better understand how just this one aspect can be detrimental to fuel consumption. 

Remember that the greater the rolling resistance a car has to endure, the more fuel the vehicle will require to remain in motion.

Weight

Typically, the larger the tire, the heavier the tire is. 

A heavier tire will impact the vehicle’s overall weight, and a heavier car will need more fuel to move it forward.

In some instances, you can offset a heavier tire and its adverse effects on fuel economy by changing to an after-market wheel made from a lighter material.

However, this option is not feasible for every vehicle and could cause more problems concerning the car’s weight distribution.

Tread

Your rolling resistance is stronger based on how thick and durable your tread is, but that harms your car’s fuel efficiency. 

Unfortunately, the ability to handle rough terrain and tackle off-road driving comes with the disadvantage of a higher fuel bill for your car or truck. 

Contact Patch

The contact patch is the section of the tires that touches the ground. 

The shape and size of the contact patch can affect the handling, traction, performance, and last but not least, the car’s fuel economy. 

Typically, you bet more rolling resistance with larger contact patches (bigger tires). That translates to fewer miles per gallon. 

If you have a wide contact patch, your traction is generally better, which is critical for those that want to use their vehicle for off-road use. 

However, better traction intrinsically makes the tires more challenging to spin, employing more fuel. 

Aerodynamics

Aerodynamics is a crucial component in decreasing gas mileage. There is a higher wind resistance with a bigger tire with a larger surface area. 

Even if your tire is just slightly more prominent and barely sticks out of the wheel well, it gets more wind than the tire that the car originally came with that’s flat against the wall. 

Sometimes when people install larger tires, they have to modify the undercarriage, or they might have to change the suspension system and lift the vehicle. 

Both of those modifications can cause drag and decrease the car’s aerodynamics.

Torque

Smaller tires have better fuel efficiency, but the manufacturer has already put tires on the car for each make and model that allow for maximum fuel efficiency. 

That means they should work optimally with the axles, transmission, and motor. 

When you change your tires for bigger wheels, it can offset the balance already in place. It can effectively change the motor power. 

When you’re revving your engine, it expends twisting or torque force on your axles, and that also creates more pressure on the tires. 

Larger tires don’t increase or decrease the torque level in the wheel, but it does diminish the amount of effective power that the wheels can exert while driving. 

The reason is that the torque is spread across a wider diameter. Therefore, the engine works harder to keep the larger tire rotating; thus, you use more fuel. 

This isn’t as much of a problem when the car is traveling at high speed because the momentum also does some of the work. 

The bigger circumference of the car or truck can use fewer revolutions per minute (RPMs) to cover more square feet.

It’s more so in urban areas that the larger tires affect the fuel economy, traveling at a slower speed. 

Other vehicles, like sports cars and muscle cars and many cars that require diesel fuel, have various torque systems and gear configurations that focus on acceleration. 

That matters because the acceleration neutralizes the effects of larger tires on these models. 

However, because sports cars and the like are generally lower to the ground, you can’t fit super large tires on them anyway, but some have larger tires than they came with.  

Wrap Up

Individually all of the factors listed might not seem like a big deal, but if they’re all working in unison, it can have a drastic effect on the car’s fuel economy. 

Ensure that you understand the consequences of adding larger tires to your car and if you’re willing to sacrifice your fuel economy for them. 

Oversized tires may look cool to some people, but they’re not always worth the investment once you realize how much MPG you’re sacrificing for aesthetic purposes.