Why do Jeep Wranglers get Bad MPG?


Why do Jeep Wranglers get Bad MPG? #JEEP #wrangler

If you’re here, you probably own a Jeep Wrangler or would like to, but are frustrated because of the notorious fuel economy.

Jeeps are some of the most inefficient and un-aerodynamic vehicles that the US makes – aside from some heavy-duty trucks. This might make people wonder why a car the size of a Jeep Wrangler would even get such terrible miles per gallon.

Why do Jeep Wranglers get Bad MPG?

So why do Jeep Wranglers get bad mpg? The two most significant factors affecting a Jeep Wrangler’s low MPG are the poor aerodynamics of the vehicle and its overall weight. The Jeep Wrangler is shaped like a box and weighs 3970 pounds without anything else in it. 

Jeep wranglers average roughly 13-18 MPG depending on where and how you drive it. Although, today’s jeeps are made to be more fuel economical, providing 22-29 MPG.

Making Sense of the Jeep Wranglers Poor Fuel Economy

There are a myriad of things that affect a Jeep Wrangler’s fuel economy. Let’s walk through what exactly slows down a Wrangler in the aerodynamics department first. 

Aerodynamics 

The top concern when thinking about the aerodynamics of a vehicle is to reduce drag, wind noise, and stopping unwanted lift forces that are caused by driving at a higher speed. In this case, the air is considered a fluid, because of how easy it flows. 

A Jeep, generally, is heavy and box-like. This shape makes it harder to cut through the air at highway speeds, causing you to burn through more gas at a faster rate. The more surface area that air has to touch, the slower the car will go. 

The Jeep Wrangler alone doesn’t have a shape that lends itself to good gas mileage. On top of that, owners often add additional features that severely affecting the aerodynamics. 

Hood Latches

The Jeep Wrangler is horrible and notorious for fluttering its hood. This is when air gets inside and is unable to get out. Typical stoke latches are made of rubber, and which are malleable. This allows the hood to flutter, as the hood is not locked down tight. 

When the air gets trapped inside your hood, it slows down the Wrangler even more, similar to hitting a wall. As the aerodynamics of the Wrangler are already rather poorly designed, this small factor can make your Jeep work harder as it fights against the wind under its hood, making you burn through gas quicker. 

Lifted Body 

A jeep will leave the factory with a bit of a rake in the nose, meaning the nose pointed downward compared to the rest of the body. The higher the body of your Jeep sits, the lower an air vortex is created. This severely decreases the aerodynamic flow of your Jeep, causing you to use even more power and gas.

Added Features  

Any added features that prevent airflow from going up and over your Jeep will lower the gas mileage, too. These features include:

  • Big bumper
  • Wench
  • High lift
  • Light bar
  • Large tires sticking past the fenders
  • Large fender flares acting as a scoop

Each of these added features decreases the aerodynamics of your Wrangler. 

Why do Jeep Wranglers get Bad MPG?

Weight Slows Down the Wrangler

A Jeep Wrangler weight averages somewhere between 3970 and 4449 pounds right out of the factory. 

Why is it so heavy? Well, a Jeep frame is built entirely of steel. The doors, hinges, fenders, a hood, and windshield frame are all created out of high-strength aluminum. These two metals weigh the vehicle down quite a bit, even if it’s for a good reason. 

These babies were made to last and to play rough. Here are some additional causes your Jeep is weighing so much. 

Tire Size (Rolling Resistance) 

Typically, a Jeep will come with a tire weighing approximately 36-73 lbs. That is multiplied by four tires plus the additional spare tire that is so iconically placed on the very back of the Jeep. With this, you’re looking at about 180-365 lbs of extra weight. 

When you’re in ownership of a Jeep, it’s easy to want to go crazy with upgrades and cool additional features for your vehicle.

Usually, one of the most popular upgrades would be more substantial, better wheels. As you increase the tire size, you’re also increasing the weight and rolling resistance of those tires. 

Adding 20 lbs or tire weight is a lot different than putting an additional 20 lbs in the trunk. Tire rolling resistance is the energy your Jeep needs to push those tires and maintain a steady speed.

So an extra 20 lbs makes a massive difference in the amount of power needed to keep your vehicles speed. 

Excess Overload on Jeep

Most people are naturally filling their Jeep with a bunch of unnecessary overloads.

Whether that be, gear storage, tools, etc. Every pound you put in your Jeep is hurting your fuel economy. Even if you only need the tools on your backcountry adventures, it will help your gas mileage to take out the extra gear when just riding around town. 

The tire carrier and spare tire itself weigh an additional 50-100 lbs. Consider daily use items and travel features like rooftop tents, and you’d be surprised with how fast the weight adds up on your Jeep. 

Bumpers and Flares

The flares of a Jeep Wrangler are usually made of aluminum, adding even more weight to the body of your Jeep, although it is possible to find plastic flares.

Plastic flares are the way to go, as they will not only help with the aerodynamics of your Jeep but also shave you a few unnecessary pounds. 

Usually, the bumper of a Jeep Wrangler will be made of steel. Again, these heavy gauged plates are only causing you more and more additional weight to drive around.

Replacing your bumper with plastic would significantly help in the aerodynamics and fuel economy of your vehicle.

Tips and Tricks to Help Save your Wallet

Most people, when thinking about buying a Jeep Wrangler, aren’t really thinking too hard about fuel economy in the first place.

This is because the fact is, Wranglers, due to a variety of previously mentioned factors, fuel economy is not the focal point. Regardless, here’s a few tricks to help save your wallet. 

Engine 

If you can, try to find a Jeep with four cylinders. The four cylinders will be geared lower and therefore spin at a higher RPM than a six cylinder.

This set up gets better mileage on the roads, although you lose a bit of that marvelous Jeep power.

Additionally, as with any vehicle, it’s important to keep the engine of your Jeep Wrangler well maintained. Check it regularly, if you see a build-up of carbon intake or deposits, clean it out with sea-foam

Regearing Your Tires 

Re-Gearing may quite possibly be one of the best and simplest ways you can save the fuel economy in your Jeep. Re-gearing is the process of actually changing your axel gear ratios. 

Although simple, it is also the most expensive step you can make. The price for this process will be anywhere from $1,500-2000. Regearing will significantly help increase your driving ability on and off the road. This, in conclusion, helps your overall fuel economy as well. 

You’ll learn that when regearing your tires, you’ll want to go with a lower gear for a bigger tire.

By regearing to a smaller gear, you’ll help increase the amount of force being sent to the axle, allowing your Jeep to drive with less strain on the engine. 

Plastic Flares and Bumper

Consider replacing your aluminum and steel made flares and bumpers with that of plastic. You can find cool, fresh designs to match the cleanliness and desirability you’d like. 

One feature that would benefit being made of steel would be hood latches. Replacing the manufacture’s hood latches with stronger ones to help with the aerodynamics of the car.  

Utility Trailer for Heavy Loads Rather than Weighing Down Jeep

If you do like going on long trips or camping trips, consider getting a small utility trailer to attach to your Jeep and pull, rather than putting all those supplies in the back of your Jeep.

This will increase fuel economy on the trips rather than loading your Jeep down with 400+ lbs of supplies. 

Low Gas Mileage? Still Worth It

The joy of driving a Jeep Wrangler is second to none for those seeking to hit some gnarly Jeep roads.

So, be prepared for poor gas mileage, but know there are quite a few changes you can make to improve your fuel economy if you want. 

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Kern Campbell

I've had a passion for four-wheel-drive vehicles since I was a kid riding in the back seat of my Grandfather's Jeep Grand Wagoneer. I have owned a lot of vehicles over the years. They each have their pros and cons and I look forward to sharing my knowledge with you so you can find the vehicle that's just right for your needs.

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