The True Effects of Tire Pressure

 

As vehicles have evolved over the years from the sub-50 horsepower early automobiles to the luxurious hypercars pushing over a thousand horsepower today, so too has the rubber that connects them to the road.

Technological innovations in one area tend to require advancements in another to keep everything aligned. In the case of tires, it’s pretty tough to imagine the tires on an early automobile standing up to the intense beating a modern sports car is capable of handing out. Innovation in vehicle power and performance has led to innovation in tires out of necessity.

Of course there’s more to tires than simply responding to increased power. The technological advancements in vehicle handling, safety, and comfort have all helped influence tire design and engineering over the years.

Today, we see tires everywhere – cars and trucks, motorcycles, wheelchairs, construction equipment, lawnmowers, airplanes, tractors, and pretty much everywhere in between. Tires have become such a common occurrence in daily life that they are an afterthought to many people. However, there’s a lot more to tires than simply serving as a buffer between a wheel and the pavement. They matter for things like ride comfort, road noise, braking, steering, acceleration, and load capacity to name a few.

So tires are important. In fact, tire manufacturing is a 4 billion dollar/year industry in Canada alone. Despite seeing them everywhere, and often using them in one way or another throughout the day without really thinking about it, one of the most important factors in tire performance, pressure, is often overlooked.

Since it’s so easily overlooked, it begs the question, does tire pressure really matter?

Short answer: yes.

Vehicle and tire manufacturers set recommended air pressures for a reason. Based on a variety of factors like vehicle weight, performance, wheel size, suspension, and many other things, a recommended tire pressure is developed for the purpose of ideal tire performance.

That ideal performance looks different for every tire and application –tires are designed for gripping snow and ice, climbing rocks, supporting a semi-truck’s weight and standing up to long periods of driving, providing a quiet, comfortable ride in a luxury sedan, or again, pretty much anything in between. The pressure for every tire and every application can be different, and it’s important to know the recommended range for your vehicle and how it can affect things like tire wear, vehicle control, and even fuel economy.

Why is tire pressure important?

So tire pressure is in fact important. But understanding why it deserves attention sheds some light on how it can affect different aspects of the overall driving experience.

Essentially, a recommended tire pressure is the ideal amount of air in a tire so that the shape of the tire is not significantly altered. Having the correct tire pressure ensures that the weight of the vehicle is distributed evenly on the tire itself. Too much or too little air changes the physical shape of the tire and alters what is referred to as the “contact patch” – the actual amount of rubber touching the road surface. In most passenger vehicle tires, the contact patch is actually only about the size of an adult’s hand. With an area that small, even the most modest changes in tire pressure can have a dramatic effect.

A properly-inflated tire ensures that the contact patch is using the tire tread most evenly and effectively. Under-inflation often results in excess stress and use on the outside of the treads, and over-inflation creates a slight oval shape in the tire, which reduces the size of the contact patch, and puts stress on the centre of the tread.

There are three major factors that are affected by different tire pressures – wear, control, and fuel economy. Inflation levels affect each differently and knowing those differences can save money and even improve vehicle safety.

Wear

Put simply, improperly inflated tires wear faster and/or unevenly. Left unchecked, this can result in the need for new tires far earlier than anticipated. Knowing what different tire wear patterns mean can often offer a pretty good hint at what’s going on with your tire pressures, or sometimes even provide some insight into issues with suspension or control arms.

While tires can wear in a variety of ways, there are really only two major signs of an improperly inflated tire. Under-inflation or low tire pressure will start showing signs of excessive wear on the ‘shoulder’, or outside part of the tread. If the outer part of the tire is smoother than the middle of the tread, there’s a good chance a tire doesn’t have enough air in it.

Over-inflation wear isn’t always quite as obvious as wear from under-inflation, simply because on some passenger vehicles, it’s easier to see the outer parts of the tire than it is to see the middle. In an over-inflated tire, more of the middle of the tire touches the road and carries the vehicle load, therefore the center of the tread will experience more wear.

When there are patches of the tire carrying more of the load, they’ll wear more quickly than a tire with even weight distribution. Unevenly worn tires generally require replacing more often to prevent leaks, blowouts, and loss of control from having no traction.

Control

Considering that contact patches are roughly only the size of a human hand, it’s not a stretch to assume that tire pressure is important for the handling and control of a vehicle. The tread patterns on tires are designed so that the driver will get the most performance when the tread is contacting the road evenly.

As seen with wear patterns in improperly inflated tires, under-inflation results in the sides of the tire having more contact with the road than the center of the tire. Under-inflation can cause excessive flex in the sidewall of the tire, which changes handling characteristics (not to mention leaves tires vulnerable to potholes). Essentially, this means that the tire is not getting all of the grip it is capable of, which can result in a loss of control when cornering and braking. In fact, a tire just 25% below its recommended pressure is 3x as likely to be involved in a crash.

The dangers of over-inflation are just as prevalent. When a tire has too much air in it, it reduces the contact patch even more. The decreased contact patch means less rubber is on the road, which opens the door for a sudden loss of grip.

Fuel Economy

One of the more common questions about tire pressure is “does it affect fuel economy?” Simply put, yes. The U.S. Department of Energy claims that under-inflated tires can lower gas mileage by about 0.2% for every 1 psi drop. That’s not a lot for most people, but it can add up over the weeks, months, and years if you consistently ignore your tire’s pressure.

For businesses that operate fleets, a little goes a long way. A small fleet of 10 vehicles can see a loss of 2% for having tire pressures off by just 1 psi in each vehicle. The numbers grow exponentially as vehicles are added and psi is lowered.

If under-inflation causes a loss of fuel economy, then the common claim that adding air to your tires improves fuel economy makes sense. Less rubber on the ground means less drag, and less power required to keep the wheels spinning, right?

However, that isn’t the case. There is plenty of information based on tests and studies that prove that ideal fuel mileage comes from having tires inflated the recommended pressure. This company found that their employees could save an average of $112/year by ensuring tires remained properly inflated.

For the average consumer, $122/year is a nice little bonus. Add the extended tire life and better ride, and it just makes sense to monitor tire pressure. For fleets and businesses with multiple vehicles though, it is more than just saving a few bucks.

Remotely Monitor Tire Pressure

Fleets tend to see significantly more miles than the average commuter. More time on the road, more fuel burned, and more tire wear. All of these factors can cost money. Swapping out tires across your fleet at painfully short intervals because of uneven wear or blowouts can add up in a hurry.  Add this to fuel prices, and it just makes sense to ensure proper tire inflation across the board.

The added benefit of proactive tire pressure monitoring is safety. Checking tires often will increase the likelihood of noticing uneven wear, defects, leaks, etc. With the proven handling benefits of a properly-inflated tire, you can’t afford not to pay attention to such a simple factor.

Titan GPS can help make checking tire pressure and health easy. Our popular maintenance manager can remind fleet managers, mechanics, and drivers to inspect, rotate, inflate, and change tires at intervals that make sense for your vehicles and your business.

To make things even easier, with Titan GPS’ Advanced Vehicle Diagnostics, fleet managers can access the OBDII data of many light-duty vehicles – including tire pressure. This feature enables users to see the current tire pressures of light-duty fleet vehicles right from the Titan GPS dashboard.

Keep drivers safe, save money, and avoid unnecessary wear and tear by integrating the Titan GPS maintenance tracker into your fleet management practices. Request a free demo and see how we can help your business in ways you never expected.

 

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