How to Choose The Best Air Compressor For Your Car

Many car owners do not pay attention to their wheels, but tire inflation is more important than you think. In your owner’s manual, you will find the optimal tire pressure recommended by your vehicle manufacturer for the ideal balance of tire wear, handling and fuel economy. Both under-inflated tires and over-inflated tires can negatively affect fuel efficiency and maneuvering. They also make tire tread wear out unevenly, which means premature replacement.

To achieve optimal performance and maximize the lifespan of your tires, you will need an air compressor or tire inflator. Read on to find out the different types of air compressor for automobiles, how to choose the best air compressor for your vehicles, and how to use it as well as tips for keeping your tires in tip top shape, one of the most basic of DIY car maintenance.

Why You Need An Air Compressor

While some modern vehicles these days come with what’s called a tire pressure monitoring system (TPMS), they are not a substitution for a portable or air compressor. That’s because these systems only illuminate a warning signal on the dashboard to notify you that air pressure in any tire is 25 percent below the manufacturer’s recommended level.

A TPMS does not inflate the tire automatically for you, and by the time your dash is illuminated, you’re already sacrificing handling and fuel economy. And note that tires can lose air over time even if you don’t have a puncture. Your tire pressure is measured in PSI. It is estimated that for every 3 PSI below the manufacturer’s recommended pressure, your vehicle is using 1 percent more gas and your tires will wear 10 percent faster.

But this does not mean you should just over-inflate your tires to prevent pressure loss. Both under-inflated and overinflated tires can have numerous negative impacts on your fuel efficiency as well as driving experience, and both result in uneven tread wear.

Under-inflated tires: Soft tires will have larger contact areas with the road. Too much traction with the road means your car needs to work extra hard to maintain its speed, thus will eat up more gas than usual. Increased contacts also means the tires will wear faster and build up excess heat as you drive, which can result in premature failure. Under-inflated tires also negatively impact the vehicle’s braking and handling, thus compromising your safety.
Over-inflated tires: Over-inflated tires are more of a problem on bumpy roads, as they will amplify the physical impacts and make for an extra rough ride. This will affect handling and braking, and cause uneven tread wear as well as premature wear and tear on your tires. Stiff tires are more easily damaged by potholes.

To keep your tires in the optimal pressure range for optimal fuel economy, handling and tire lifespan, you need to get the best air compressor to conveniently and routinely check your tire pressure and make adjustments if needed. Purchasing an air compressor will save you money on premature tire replacement, thus is well worth the small investment you paid for it.

Air Compressor Basics

air compressor for car tires — Having an air compressor on hand would ensure your tires are up to specs, which means optimal handling, fuel economy and tread wear. Photo Credit: The Manual

Tire air compressors are not to be confused with your average air pump. Air pumps suck in the surrounding air and move it into another place without pressurizing it, for example when you’re pumping up your air mattress.

Meanwhile, an air compressor converts the electrical energy produced by your battery or engines into kinetic energy and stores it as pressurized air. This pressurized air can be used to inflate tires and fill gas cylinders, as well as powering tools such as jackhammers.

You might be wondering why there are two terms, air compressor and tire inflator. A tire inflator is a specific type of air compressor which is portable and is used for inflating the tires of an automobile. They come in different shapes and sizes as follows:

12-volt Air Compressors

12-volt air compressors are very convenient, although they are not powerful enough to get the job done quickly. This type uses your car’s built-in 12-volt cigarette lighter, or a standard power outlet, while more powerful air compressors that fill up tires quicker will often need to hook up to your car’s battery. They are still affordable and sensible options when you don’t want to pay to use an air compressor at a gas station. Most gas stations will have an air compressor, but some stations charge and some don’t.

Hand-Carry Air Compressors

Hand-carry air compressors are the most lightweight, compact and portable. They are convenient to move around, so you can bring them along during long road trips to take care of your tires. This type of air compressor is mostly electrically-powered, with some exceptions of gasoline-powered models.

In addition to inflating car tires, handy-carry air compressors can handle other light-duty applications, including inflating balls and mattresses. They are available in a variety of sizes, that is cubic feet per minute (CFM), an important criteria that will be explained further below.

Wheeled Portable Air Compressors

This type of air compressor is also portable, but they are much heavier than the hand-carry type, so they need wheels to be pushed or pulled to wherever they are needed.

Portable air compressors with wheels are available as either electric or gasoline-powered. They can also be classified as either having vertical or horizontal tanks.

Mobile Air Compressors

Mobile air compressors are mounted to or towed behind a truck, so they are as portable as the vehicle they’re attached to. They come in all sorts of shapes and sizes, and each sub-category has very unique features and applications.

Tow-behind compressors are often used with construction trucks, while truck-mount compressors are often used on road-side service vehicles. This type of air compressors are designed to inflate punctured tires and power air tools on the go. This makes them an ideal addition to bring along on off-road trips.

Air Compressor For Car Tires: Buying Guide

PSI Range

Tire pressure is measured in PSI, which stands for pound-force per square inch. One important criteria when shopping for an air compressor is the maximum PSI at which it can inflate your tire. For inflating car tires, you will only need to run them to between 30 and 35 PSI for most passenger cars.

Meanwhile, SUVs and light trucks might require a bit higher PSI levels, and larger trucks, especially when hauling or towing, would require tire pressure of 75 PSI up to 110 PSI. Travel trailers and motorhomes would require tire pressure of up to 150 PSI, sometimes more.

On cold days, you probably should inflate your tires more, as in lower temperatures, the air inside is condensed, thus reducing the tire pressure. Check the optimal pressure in different weather conditions in your manual, or typically on a sticker inside the driver’s-side door jamb.

Flow Rate – CFM

The flow rate of an air compressor, or the amount of air that a compressor can produce at a given pressure level is measured in cubic feet per minute (CFM). While you might think that the maximum PSI that a unit can be set to is important, it is not the most important factor. Instead, you need to pay attention to CFM, one of the most crucial metrics in choosing the best air compressor to inflate your car tires.

Typically higher CFM ratings means that a compressor is capable of providing more air within the same time, which makes them ideal for larger applications. In other words, they can inflate your tire to the recommended pressure level faster.

A portable air compressor rated for 1 or 2 CFM, at 90 PSI, should serve you well for the task of filling your tires. If you want to use your air compressor for other hobbies or to run some tools, the rule of thumb is the minimum CFM you need for your air compressor should be 1.5 times the total required CFMs of the tools. For instance, if you need to run a spray gun with a CFM of 4 at 40 PSI, the air compressor should be capable of at least 4 x 1.5= 6 CFM.

Multifunctional

Nowadays, although designed primarily to inflate car tires, air compressors for automotive use are often multi-functional. They have been adapted to also power tools such as tire changing machines or spray guns, and inflate bicycle tires, as well as any inflatable items such as inflatable pools, compressor and sports balls. If you need a multifunctional air compressor for use around the house or for hobby work, just look for an air compressor that comes with a plug for multiple home use.

Ease of Use

A portable air compressor that’s easy to carry around will give you the most use around the house, with the car and on the go. If possible, you can shop in the store to check for yourself if it’s lightweight enough to carry around, if it is compact enough so as to not take up much space in your cargo area, if it is comfortable to hold, and if the unit is well designed and solidly constructed.

Since you’ll want to store your air compressor in the car so that you can reach for it whenever you need it, you will want a model that comes with a solid storage case. Also, if you plan to store the air compressor in and around your car, you will want a model that can reach all the tires with as little effort as possible.

Resistant to Overheating

Note that a common problem with the most portable air compressors on the market is they can heat up during operation, and it can lead to melting and burning. And these mishaps can happen even if the unit has an overheating protection function which would shut it down as soon as it overheats.

Some portable air compressors for automotive use heat up so quickly that they can only work for a short period of time before immediately shutting off. This means that even when a unit can reach a high PSI level, for instance above 100 PSI, which is what is needed for large trucks and motorhomes, it would not be of much use if it easily overheats and shuts off every few minutes to cool down. If this is the case, it would take forever to inflate your tires to the required level.

If you are buying the air compressor for your tires and you own a regular passenger car, the recommended pressure would typically range from only 30 to 35 PSI or 40 PSI at most. This means PSI is not the most or only important metric, but how long the air compressor can work without overheating is also crucial.

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Tire Pressure Maintenance Tips

Know the Recommended PSI

You can find the manufacturer’s recommended tire pressure on a sticker located on the driver’s side door jamb in most vehicles. If you cannot locate this sticker, check your owner’s manual or the manufacturer’s website.

Pay close attention to the values listed on the sticker, as some vehicles have different recommended pressures for the front and rear tires, especially in the case of large trucks intended for heavy towing or hauling jobs. For example, some trucks might require 55 PSI for front tires and 80 PSI for rear tires.

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How to Properly Inflate your Tires

If you’re using a compressor at a gas station, pull in as close to the compressor as possible so that you can easily access all four tires without difficulties.
Remove the valve stem caps from all four wheels (and put them in your pocket so you won’t lose them).
Turn on the compressor and push the hose fitting down on the valve stem. Digital air compressors will allow you to set your desired tire pressure. The unit will automatically shut off once it reaches that desired pressure.
Most air compressors will have a built-in gauge that allows you to check the existing tire pressure during inflation. So it’s more convenient to overinflate your tires by a bit, then simply release some air afterwards until the gauge indicates that you’ve reached the desired PSI level.
Note that it’s best to inflate your ties at home when the tires haven’t been driven on, which would create heat and mess with the measurement. Park your car for at least three or so before proceeding with the compressor. But if you are using the compressor after your tires are warmed up, inflate about 3 PSI over the recommended level. Once your tires are cold, make sure to check your tire pressure again with a digital gauge.
Put the valve stem caps back in.

Check Your Tire Pressure Regularly and How To

A basic car maintenance routine is to check your tire pressure using a digital gauge once a month or so to make sure they’re as close to the recommended PSI as possible. This will ensure optimal performance and help your tires last as long as possible. Car tires don’t come cheap. Follow the steps below to check your tire pressure using a tire pressure gauge:

While standard, analog tire pressure gauges are cheaper and can get the job done, a digital gauge is more accurate and easier to use and read.
To get an accurate reading, make sure the tires haven’t been driven on, which would create heat and mess with the measurement. Park your car for at least three or so before proceeding with the tire pressure gauge. Remember that the recommended tire pressures listed in the manual and on the sticker in the driver’s door jamb are for cold tires.
Remove the valve stem caps from your tires. Apply the pressure gauge to the valve stem, making sure you form a good seal between the gauge and the stem. Then, release air from the tire into the gauge (when you do this, the pin inside the gauge will press against the pin inside the valve stem).
A plastic rod will extend from the gauge to give you a pressure reading.
If the pressure is higher than the recommended level, most of the best tire pressure gauges will also allow you to release air from your tires by putting the opposite end into the valve stem.
If you’re using a standard pencil gauge or any non-digital gauge, it’s always a good idea to perform the check two or even three times to make sure you have an accurate reading.
Reinstall your valve stem caps.