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When it comes to discussing car maintenance, tire pressure is one subject that too often gets overlooked. However, the fact of the matter is, keeping the right amount of air in your tires affects so many aspects of your vehicle’s performance, safety, and cost to operate that it should be a priority for every driver. Not to mention, it doesn’t require any specialized training to do it yourself.

We’re going to look at some of the basics as to why tire pressure is so essential, and provide you with some tips to help you keep your tires properly pressurized and rolling right. 

The first thing to know is that tire pressure is measured in PSI or pound-force per square inch, and every vehicle has a specific recommendation for the exact number required to keep things running smoothly. Usually found inside the driver’s door jamb or in the owner’s manual, the PSI number provided has been safety-tested by the manufacturer for your car. It’s critical to keep in mind that while your tires will have a pressure range stamped on them, you need to follow the operating pressure set out by the carmaker. Even if you have the inflation within the tire’s acceptable range, it can still be problematic for that tire on your specific automobile. 

Once you have the correct PSI, checking the tire is a pretty straightforward task. Below is our step by step guide to doing it yourself. 

Checking Your Tire Pressure

  • Tire Pressure should be checked “cold” before you’ve driven the car or about three hours after to ensure an accurate read
  • Remove the valve cap from the valve stem – (If the cap is missing, be sure to pick up a replacement to prevent debris from building up in the connector)
  • Press the head of your pressure gauge onto the end of the valve stem to get a reading (it’s typical to hear air hissing when you press the gauge)
  • As soon as you get a number (either on the digital screen or on the stick of a pencil-style tire gauge) remove the device from the stem
  • If the pressure is too high, use the nob on the back of the gauge to press the pin into the valve stem and release some air and repeat test
  • If the tire is underinflated, take the vehicle to the nearest gas station or auto garage, add some air and repeat the test

Proper tire inflation will allow you to have the best possible control of your vehicle and provides you with a more comfortable ride. However, over or underinflation can cause a variety of different problems.

The Trouble with Over Inflation

When it comes to overinflated tires, the trouble is they become inflexible, and result in a reduced amount of surface area being in contact with the road. With more rigid rubber, the tires have a decreased capacity to absorb shocks from imperfections in the street and are more likely to rupture if you were to hit a pothole. The reduction in contact area created by overinflation causes uneven tread wear, usually referred to as “centre wear.” This means tires end up smooth in the middle with more tread on the outside edges, leading to a decrease in traction and an increased stopping distance.

The Trouble with Under Inflation 

Underinflated tires, on the other hand, have trouble holding their shape, allowing too much of the rubber to be in contact with the ground. The US Department of Energy has published that for every 1-psi drop in pressure, you can expect your gas mileage to lower by 0.4 percent. Now, not only does this extra friction, or rolling resistance, cause an increase in fuel consumption, but it also creates “shoulder wear.” This irregular wear pattern is the opposite of “centre wear,” in that there is a strip of regular tread down the center of the tire, while the shoulders become smooth and worn down. With the combination of soft rubber and “shoulder wear” resulting from underinflation, you will notice reduced agility and considerable amounts of understeer. As the tires are generally slower to respond to turns, you end up with what feels like a mushy ride.

Of course, both over and underinflation will cause undue wear on your tires and require that you change them more regularly. Incorrect tire pressure is estimated to reduce your tire life by upwards to 15,000 kilometres. Adding a considerable extra cost to operating your vehicle. 

Make Tire Pressure Part of Your Routine

When it comes to inspecting your tires for the correct PSI, it’s ideal to do it least once a month, and it’s essential that you use the same gauge each time.

For those that have trouble remembering, add a reminder to your Smartphone, or if you use a paper calendar, you can write PSI in black letters on your preferred day of the month.

If you don’t have a tire pressure gauge, the pencil-style analogue variety can be purchased quite inexpensively at most gas stations. However, if you find reading the pencil-style gauges challenging, an affordable digital option may be better to ensure you actually use it to test your tires regularly.

We should also mention that when it comes to tire pressure, looks can be deceiving. In recent road tests, track results were compared between a car with properly inflated tires and again for the same vehicle with its tire pressure decreased 20 percent below the recommended level. While the difference was undetectable to anyone looking at the wheels, the ability of the car to negotiate the track was severely hampered by the marginally reduced air pressure.

Keep Track of the Seasons

When you get into the habit of monitoring your tire pressure every month, it’s essential to remember that the seasons can have an effect on the PSI. Tire pressure can vary 1-2 psi for every 10-degree difference in ambient temperature, which means psi typically increases in the summer heat and decreases when it’s cold outside. When doing your monthly check, you can adjust the pressure as it fluctuates throughout the seasons to ensure you keep your tires at the correct level.

A Tire Pressure Monitoring System isn’t Good Enough

After a series of accidents attributed to tire pressure in the United States, Congress passed a law requiring a Tire Pressure Monitoring System (TPMS) in all cars after the model year 2008. A good number of Canadian vehicles have followed suit. Still, the technology is not mandatory in this country, and not all cars come equipped with TPMS. Of course, it’s worth noting that most monitoring systems don’t alert the driver until the tire pressure falls below 25 percent underinflated, based on the manufacturer’s recommended PSI. As we noted before, your ability to control your vehicle has been substantially compromised when the tire is 20 percent underinflated. The goal of the system is not to keep the driver informed that the tires are correctly pressurized, but rather to warn against the potential of a catastrophic failure. For this reason, we strongly recommend against relying on a TPMS to monitor your tire pressure and continue to perform your monthly inspections, even if you have the system on board.

Talk to a Tire Expert

At Sipan Tires and Rims, we regularly monitor the tire pressure in our customer’s vehicles to ensure they are correctly inflated. However, as we don’t see most cars every month, it’s crucial that you know how to do this quick assessment on your own. If you’re finding it challenging to test your tire pressure or want some advice on the best gauge to suit your needs, our tire specialists are here to answer all your questions. Give us a call: 613-695-8866 or drop by for a quick tire pressure demonstration today.