How many cars have tpms

It does not employ tire-pressure sensors in the tires, relying instead on the anti-lock-braking system's wheel-speed sensors to determine if any particular tire's rotational speed is out of sync with the others. This indicates that the suspect tire's circumference has changed and that it could have lost air pressure. To ensure that your vehicle's TPMS system's pressure sensors remain operational for as long as possible, always reaffix the valve-stem cap after checking air pressure or inflating the tires.

This helps prevent valve-stem corrosion, particularly where salt is used to clear the roads in the winter. If the TPMS warning light does illuminate—the light looks like a flat tire as viewed from behind the car—check your instrument cluster display and then use a tire-pressure gauge to check all four tires to determine which ones, if any, are low.

Fill them to the manufacturer's recommendation as soon as possible, remembering that, if you've driven several miles to get to an air hose, your tires will have warmed up and you should inflate them evenly.

For example, if when you get to the gas station one tire is at 20 psi and the other three are at 34, bring the low tire up to the other three, as long they are at or above the vehicle manufacturer's recommended pressure. However, if the TPMS warning comes on again after a short period of time—hours or days—you most likely have a leak in one of your tires.

Get to a tire store and have it repaired without delay. Driving on a badly underinflated tire can destroy it; worse yet, it can cause you to lose control of your car and have an accident. Finally, for drivers who keep a set of winter tires mounted on a second set of wheels for use in the snowy months, we recommend having compatible TPMS sensors installed on the second set of tires, too.

That way, you're covered no matter the season or which tires you have on at the time. After all, we wouldn't want you to feel, ahem, deflated by getting a flat.

Many kinds of tire pressure gauges are available today that vary in size, shape and price. Here's a selection to choose from. This is the gauge that we gauge good enough to use in the Car and Driver test garage. We set all of our test vehicles' tire pressures precisely to ensure that they perform their best in our comprehensive testing program. This low-cost Accutire digital gauge works beautifully. It reads in half-pound increments, so you can set your tires' pressures as accurately as we do.

This analog gauge is to modern digital gauges what a typewriter is to a laptop computer. While it's ancient technology, it's still far better than nothing, and it will help you to keep your tires in the correct inflation range—and do it for a rock-bottom price. But we recommend and use the Accutire gauge, so that should tell you where we stand.

These sensors measure the rate of revolution each wheel is making and can be used by on-board computer systems to compare with each other and to other vehicle operation data such as speed. Based on the rate of revolution of each wheel, the computer can interpret the relative size of the tires on your vehicle. When a wheel starts spinning faster than expected, the computer calculates that the tire is underinflated and alert the driver accordingly.

Instead, an indirect tire pressure monitor simply measures how fast your tires are rotating and sends signals to the computer that will actuate the indicator light when something in the rotation seems amiss. Direct TPMS uses pressure monitoring sensors within each tire that monitor specific pressure levels — not just wheel revolution data from the anti-lock brake system. Sensors in a direct TPMS may even provide tire temperature readings.

A direct tire pressure monitor usually sends all of this data wirelessly. Each sensor has a unique serial number. When tire pressure became a national topic in the United States after a series of automobile accidents in the early s, U. Today, all new U. The realization that proper tire pressure is so critical to the safety of drivers is now truly a worldwide movement.

Many regions are making continued progress toward TPMS adoption. Primarily for environmental reasons, European countries via United Nations regulation UNECE-R64 have adopted legislation for new models beginning in November , and for all vehicles beginning in November Click here for a side-by-side comparison of TPMS legislation for different countries around the world. Low Tire pressure could be putting you at risk Canada Excerpt: More than half of Canadian drivers drive with at least one tire improperly inflated, according to Transport Canada, which could lead to a dangerous situation such as skidding, hydroplaning or losing control of the vehicle.