TPMS (Tire Pressure Monitoring Systems) Information

Kentucky Tire Exchange TPMS News Article

TPMS Federal Motor Vehicle Safety Standards

Air Pressure

The Benefits of Correct Air Pressure
Keeping the correct air pressure in your tires is as important as giving your engine a tune up. The economic benefits are perhaps even greater! With the right amount of air pressure, your tires wear longer, save fuel, enhance handling and prevent accidents. If you consider the liabilities of not maintaining the correct air pressure—poor gas mileage, loss of tire life, bad handling (perhaps even loss of control), and potential vehicle overloading—then the need to routinely add air to your tires will become clearer.

Check Air Pressure Routinely
Perhaps because our tires do so much without seeming to need any attention, we tend to overlook this important task. But tires do lose pressure, slowly but surely everyday, through the process of permeation. Generally, a tire will lose one or two pounds of air per month in cool weather and even more in warmer weather. Also, tires are subjected to flexing and impacts that can diminish air pressure. So, think in terms of refilling your tire just like you do your gas tank; actually that's a good reminder, refill your tires every other time you fill up at the gas station. That's the recommended interval. Another time to check air pressure is when the tires are rotated. Many vehicles have different tire pressures on the front and rear axle, so remember to have this adjustment made. Also remember to have the pressure in your spare checked. The space-saver type spare requires a much higher air pressure level than other tires and is virtually useless (due to overloading) at lower air pressure levels.

Where To Find Air Pressure Information
The correct air pressure may be found in the vehicle owner's manual or on the tire placard (attached to the vehicle door edge, doorpost, glove box door or fuel door). If you have trouble, see Kentucky Tire Exchange. The placard tells you the maximum vehicle load, the cold tire pressures and the tire size recommended by the vehicle manufacturer.

Another valuable resource is the Tire Load/Inflation Tables. Kentucky Tire Exchange has a copy just call us. Not only will this document tell you the correct tire pressure for stock sizes, but it will provide the information on optional plus sizes as well. A good example would be the findings on a Honda Civic with the stock size 185/65R-14; recommended air pressure is 28 psi. Plus one size is 195/55R-15 with a recommended air pressure of 32 psi. Plus two size is 205/45R-16 with a recommended air pressure of 36 psi. Note how the air pressure increases with plus sizing to meet the load carrying capacity for the car.

Other Factors Change Air Pressure
Besides the routine air check, other circumstances necessitate a visit to the air pump. Seasonal changes or altitude changes create a rise or drop in air pressure (for every 10 degrees change in temperature, tire air pressures changes 1 psi). But perhaps the most overlooked factor is vehicle loading for trucks and RVs. Since these vehicles can be configured and loaded in many ways, the proper inflation pressure should be determined by actual tire loads. This is best determined by weighing the vehicle; vehicle loading can change from trip to trip.

  Remember that tire failure can occur due to underinflation and overloading!

One of the most dangerous conditions that can exist is the slow leak. Sometimes a small nail, screw or other object will puncture a tire and then act as an inefficient plug. Air pressure drops slowly over a matter of hours or days, undetected by the driver. Your best defense in this circumstance is to be alert to the symptoms of this Be aware of any pulling or vibration that seems unnatural. And listen for any tick-ticking sound—especially audible at slow, parking lot speeds. If you detect this, get off the road and inspect the tires on the side of the pull, vibration or sound. A bulging sidewall and/or excessively hot tire indicates a slow leak. Put on your spare tire and have your tire dealer repair the punctured unit. Ask the repair technician if any sidewall damage has occurred (a powdery residue inside the tire indicates this condition). If so, have the tire replaced.

How To Check Air Pressure
Properly checking tire pressure requires an accurate air gauge. Many people believe that they can check air pressure just by looking at the tire and judging the sidewall appearance. Also, many people use the air meters at service stations, which can be grossly inaccurate due to exposure or abuse. Invest in a quality air gauge. For trucks and RVs, use a dual-head inflation gauge that is calibrated up to 120 psi at 2 psi increments.

When checking your vehicle's tire pressure, make sure the tires are "cold". Cold air pressure means that the vehicle has not yet been driven one mile (remember that driving on a tire increases its temperature and air pressure). If you must drive more than one mile for air check and record the air pressure in all your tires before you leave. Once at the tire dealer, measure each tire's inflation again and then note the difference. Inflate the tires with low pressure to a level that is equal to the recommended cold pressure plus the difference at the higher temperature.

In this example, add 3 psi in the right rear tire to match the other rear tire's warm reading. When the tire returns to cold pressure, it should end up at the recommended pressure.

Finally, after completing the pressure check, make sure the valves and extensions are equipped with valve caps to keep out dirt and moisture. Remember to replace the valve assembly when you replace the tire; it's your best assurance against a sudden or consistent loss of air pressure.

Environmental Impact
How can routine air pressure maintenance impact our environment? Consider that fewer tires per year would end up in the landfills and scrap heaps that trouble our ecology. How many tires are we talking about? We estimate that most drivers lose from 10% to as much as 50% of tire tread life due to underinflation. That's a significant statistic. Now consider the extra fuel we burn to push cars along on soft, underinflated tires. Tires do require extra energy to roll if they are under inflated. While the statistics vary widely and inconclusively, the implications are staggering. So maintaining tire pressure is a small line item in our busy daily routines, but it adds up to big environmental consequences. We must all care and take action to do the right thing.

A nationwide survey revealed that 55 % of the people who responded did not know the correct pressure recommendation for their tires or where to find it.

Teamwork for Tire Safety

Now that the topic of tire safety has risen to a new level of awareness, it might be a good time to consider that you and Kentucky Tire Exchange can work together as a team to improve your safety. For those of us in the tire business, there is no question that maintaining the correct air pressure in your tires is the most critical factor for tire safety. Let's take just a minute to see why.

A tire is essentially an air envelope that has been engineered to support your vehicle's weight. It has two key parts that connect it to the vehicle and to the road or terrain. These are the bead structure that connects the tire to the wheel and the belt and tread package that provides traction with the road. Between the two is a sidewall structure that changes strength and shape as air is added or reduced. Together these elements represent eighty years of material science and mechanical engineering advancements that have been driven by one of the most competitive markets in the world. To say today's tires are well engineered is an understatement. But this marvel of engineering is completely dependent on the correct air pressure. Without air pressure to support this structure, a tire quickly overheats and ultimately fails.

Consider that we have become dependent on tire technology, and that we tend to forget about our tires. Consider, too, that tires have a requirement that is quite like your gas tank: they require periodic refilling. But unlike your engine, a tire keeps functioning even though it has less than the required amount of air. If it were not "over-engineered", a tire would fail much sooner. But, almost incredibly, the vast majority of tires continue to function until there is almost no air pressure within the casing (interior volume). Over the years our store employees have seen cars and trucks come in with tires that have survived almost impossible abuse due to vehicle overloading and tire underinflation. Yet the tires kept on going. Thankfully, there is a significant margin for error.

So we should all agree that tires need the correct amount of air to function and last, as they were designed to do. Most people think they know the correct air pressure for their vehicle's tires. Recent surveys reveal that the majority of the people who responded did not know the correct pressure recommendation for their tires or where to find it, though most thought they knew. There are many places on our website where you can find this information, but for your convenience, here it is: the recommended tire pressure is set by the vehicle manufacturer and is in the owner's manual and on the vehicle door edge, door post, glove box or fuel door.

Just drive up to our service bay at Kentucky Tire Exchange and ask to have your air checked. We are glad to do this as a public service, regardless of where you bought your tires.

If you do one thing and one thing only to ensure your safety (with regard to tires) check the air pressure monthly, and always before a long trip. Here is a proposal to make this as fast and simple as possible. Let us do it for you. We will do it quickly, and we will do it for free. As tire professionals, we have the know-how and the tools to accurately check the air and we know the required pressure for your vehicle's tires. We will also let you know if we see any tire problems. Just come to Kentucky Tire Exchange and ask to have your air pressure checked. You?re done in minutes. We are glad to do this as a public service, regardless of where you bought your tires. Your part is actually the hardest...you have to remember to do it...along with all the other items on your to-do list.