Does Low Tire Pressure Affect Gas Mileage? Here’s Why

Low tire pressure affects gas mileage by causing increased rolling resistance, which makes your vehicle work harder and consume more fuel. Keeping tires properly inflated ensures optimal fuel efficiency and can save you money on gas.

Many people forget that tire pressure is critical to a car’s operation. How a car functions relates to how comfortable a person is in it, how safe it is, how much gas is used, and how efficient it is. These factors could change the gas mileage of a car, and the question arises of whether low tire pressure affects gas mileage. In this post, we will attempt to provide the answer, as well as how tire pressure works and how it affects the economy of a car.

Your tires contain compressed gases which enables the tires to rotate and the car to drive. A vehicle that has tires that are either too inflated or not inflated enough will consume much more fuel than is necessary. This is the basis of how tires work in economy.

What Is Tire Pressure?

Tire pressure is the amount of air in the tires which is measured in pounds per square inch (PSI). Every vehicle has a certain PSI level that is recommended in order for it to perform well. This recommendation is usually on a sticker in the driver’s side door frame and is also included in the owner’s manual.

Every vehicle has a proper tire pressure in order for the tires to optimally perform regarding traction, comfort, and safety. Tires that are overinflated and those that are underinflated do not perform well, and as a result, the vehicle will not handle well, fuel will be wasted, and the overall driving experience will be poor.

The Basics of Tire Pressure

While driving a car, the weight of the vehicle pushes down the tires, causing them to deform a bit and touch the ‘ground’. That small area, or ‘footprint’, that touches the ground is what allows a car to remain ‘stable’ and allows it to ‘move’. The ‘footprint’ is determined by how rigid the tires are and how much air is pumped.

If a tire is loose, it will be deformed more. If a tire is deformed more, there is a larger area of contact, which means there is more ‘squeezing’ and more ‘drag’, which means everyone is working harder, and the ‘squeezing’ energy is all in the gas.

How Tire Pressure Affects Fuel Economy

Low tire pressure does more than just affect the functionality of a car. It drastically lowers gas mileage which results in more fuel being wasted. This section explains the various ways in which under inflating tires affects gas mileage.

Increased Rolling Resistance

Under-inflated tires more than likely will increase gas expenditure by a hefty amount. This section gives a better understanding on how rolling resistance works.

Rolling resistance is the resistance a tire meets while on a surface. This resistance opposes the forward movement of a vehicle. It is determined by the area, the material of the tire, pressure, and what is in contact with the vehicle. When tire pressure is low, the area in contact with the tire surface is larger, meaning the tire must work much harder to roll.

If your tires don’t have enough air in them, the increased resistance caused by the rolling tires causes the engine to burn more fuel in order to maintain the speed of the car. As a result, the car burns fuel more quickly, causing the gas mileage to decrease.

One example of the tires on the car not having enough air is riding a bike. Riding a bike with underinflated tires is a struggle, because the pedaling motion is much more difficult, and a lot more energy is required. The same case works with a car–when the car moves and the tires are underinflated, the engine is forced to burn fuel in order to keep moving.

Overworking the Engine and Inconsistent Fuel Efficiency

The rolling resistance of a vehicle is not the only thing underinflated tires affect. Underinflated tires have the ability to, and will, overload the engine. When the car is driving on flat surfaces at a constant speed for a while, the engine works at a very constant rate. The same thing happens when driving on highways, and when driving uphill. All the other work just is more power from the engine, which means burning more gas.

These sorts of things are worsened when the car is going on a long trip, or when the car is going at very high speeds. When the car is going on an underinflated tires at sixty five miles an hour, that car is wasting gas in a much larger quantity than a car that is going at the same speed with the tires appropriately filled.

Gas Mileage Decrease & Tire Damage

When you don’t inflate your tires, the pressure gets unequally distributed. This uneven distribution of pressure causes the edges of the tires to wear down more quickly as compared to the center of the tires. Not only does this decrease the tension of the tires, making the road slipperier, it also traps fuel inefficiency as more energy required to spin the tires is now needed.

Worn down tires are less precise and are unable to properly align the forces acting on the tires. The excessive energy used causes more fuel to be burned. You will also have to deal with more frequent tire replacements. Repair expenses will quickly pile up as well.

Decreased safety and more fuel Burn

When tires are less bustled, there is an increased chance of an accident. The more you striker out and drive, the increased chance that tires overheats. The more the drive is done, the more the tires will be and this is also the chance oh the more the tires will blow out.

Also, in my experience, operating a vehicle with a deficiency of air in all of its tires means that the vehicle cannot be as easily controlled. For instance, in adverse weather conditions, braking is more difficult, the ability to steer declines, and the handling is overall less than desired. The same goes for worsening the driving experience in any weather. Driving in low gas conditions also means that more traffic and accidents are likely to occur. The consequences of the accidents would cause more expenses to be paid.

Where The Real World Figures Of Driving With Under Inflated Tires and Economy Come Hand in Hand

Under normal conditions, a lot of people with vehicles do not understand how the economy is affected negatively with gas under inflated tires.

Example on how a Toyota Corolla Can be Used as a Test Dummy

A patron of my lab attempted an experiment with multiple vehicles and paired it up with more wheels than it had. The goal was to learn how much gas would be consumed after driving for a while on tires with 75, 50 or no air. Apparently, the car consumed less gas than usual with 2-3 % being 75% tires under pressure.

However, overheating a car or driving it at a higher speed more than the tires can handle results in the car not being able to cope and consuming more gas. All of my earlier claims about underinflated tires are reiterations of the consequences of how my Corolla.

This case study adds to the assumption that gas mileage is always affected by the amount of air that is put into the tires. The less the air that is put into the tires, the less gas efficiency the tires would achieve, leading to more gas burnt.

Factors to Determine the Effect of Low Tire Pressure

There are a number of probable determinants that may influence the gas mileage a car obtains due to low tire pressure. They include the speed at which the car is driven, the temperature, and the surface on which the car drives. Knowing this especially for the factors that you control should enable you to make the adjustments that will reduce the amount of gas being burnt for underinflated tires.

1. Speed

The negative impact low tire pressure will have on the gas mileage of a car becomes greater with the increase in speed on which the car is driven. The difference in the resistance of tires on the ground is greater the faster you drive, and having less air in the tires makes the difference greater. The faster you are going, the more the car has to push against the resistance, and therefore, the more gas is used compared to the slower speeds of city driving.

2. Temperature

The colder it is, the less air there will be in a tire. For every time ten degrees the temperature drops in the air, you will loose on average 1-2 of pressure in a tire. This is more plumbing and plumbing of a tire, therefore you should be in the habit of checking for underinflated tires.

3. Terrain

Driving uphill and on rough uneven surfaces means that the engine has to work even harder especially if the tires are under-inflated. The work that the engine has to do is even greater the more the tires are under-inflated. Therefore, if the tires are under-inflated, extra gas will be needed so tapping into the gas if available will be costly. Hence, if you undertake planned journeys that involve uneven surfaces, check your tires before you go.

Tips to Maintain Tire Pressure for Fuel Economy

We’ve seen the link between tire pressure and fuel economy, so let’s now discuss how we can maintain tire pressure for better fuel economy, tire safety and tire pressure.

1. Check Tire Pressure Frequently

Tire pressure should be checked at least once a month. To do this, a person can obtain a digital and/or analog tire pressure gauge which can be located at almost any auto store for a very low cost.

2. Inflate tires to the recommended psi

Each vehicle is designed to operate with a specific tire pressure. The recommended tire pressure can be located on the tire placard on the inside of the driver’s side door frame and sometimes even in the owner’s manual. Make sure that your tires are inflated to that specific PSI. Overfilling the tires can result in a jarring ride, lack of grip, and even tire destruction. While we are on the subject, tires that are under inflated are just as dangerous.

3. Use a tire-pressure monitoring system (TPMS)

Several contemporary automobiles have Tire Pressure Monitoring System (TPMS) functionality that is capable of issuing alerts when a tire is under inflated. While such a system is helpful, it is still advised that you physically check the tire pressure to avoid any issues. Quite often, the system will not issue any warnings on slight pressure losses until they are very low.

4. Adjust your tire pressure to the seasonal changes

With the changes in temperature, tire pressure will also change. In the winter, cold weather has a greater ability to drop tire pressure so you must be especially careful. It is important to check your tire pressure often in the freezing weather so you can also properly ventilate your tires when necessary.

5. Have Your Tires Checked Regularly

Besides ensuring proper inflation, regularly check tires for possible abrasions, such as slashes or fractures. Tires with piercings lose air ever so slowly without immediate detection. Regular checks help bring tire issues to your immediate attention.

Correct Tire Inflation

Correctly done tire pressure saves money and helps the ecosystem.

Benefits

Correctly Inflated tires improve fuel economy and save money. For an average passenger driver, the estimated savings amounts to $150. In the course of the year, money savings from fuel alone pay for proper tire inflation.

Environmental Benefits

When a vehicle uses fuel, it tends to emits a certain amount of greenhouse gases. Lesser fuel consumption means a vehicle will produce less emission. It helps to lower carbon footprints and saves dollars as well.

Related Article
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Does Tire Pressure Lower in the Cold?

Frequently Asked Questions

Here are some FAQs about effects of low tire pressure –

1. I want to know how frequent I should monitor the tire pressure.

It is best to monitor the tire pressure with a minimum of a one month vital check, along with one check before the drive, and at least one check during the drive. The tires should also be monitored for maintenance during seasonal changes.

2. For my particular vehicle, what is the best tire pressure?

The best tire pressure lies with the owner’s manual, along with a sticker where the door is on the driver’s side tape and responds to the Automakers charge for optimal performance.

3. I head that gas mileage can be improved with over inflated tires.

In theory yes, because over-inflation tires reduce the rolling resistance, traction goes down and it increases the chances of damaging the tires. Keeping the tires at the right pressure will be your best bet.

4. Does tire pressure affect tire lifespan?

Yep, underinflated tires cause uneven wear on tires which makes tires need to be replaced sooner than they should. Maintaining the proper tire pressure on the other hand makes sure that the tires will be worn evenly and used for a longer time.

5. Does low tire pressure increase the chances of a blowout?

Certainly, tires that do not have proper inflation are more likely to overheat, which can be a cause for blowouts. Other than that, Keeping and checking the tire pressure at regular intervals can prevent overheating, and therefore blowouts and other problems.

Conclusion

Low tire pressure costs more money because tires wear uneven, use more gas, add more strain on the engine, and increase gas mileage as a result of all the sticky resistances. By skipping out on tire inflation, fuel economy gets worse, safety context goes down, the tires will wear down fast, and maintenance costs will go up like crazy. The answer? Inflation that costs nothing and improves tire life. Regular tire checks, tire inflation, and maintenance keeps these tires rolling optimally.