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Wheels and Tires:
Tire Pressure Monitoring Systems (TPMS)
As part of the effort to increase awareness of the need to maintain proper tire pressure, the U.S. government has taken steps to make it easier for drivers to be aware of potentially unsafe low pressure in their tires.
As of the 2008 model year, the National Highway Traffic Safety Administration (NHTSA) now requires that all passenger cars and light trucks feature the Tire Pressure Monitoring System (TPMS).
Automated Tire Pressure Monitoring Systems or TPMS provide a means of reliable and continuous monitoring of the vehicle tire pressure and are designed to increase safety, decrease fuel consumption and improve vehicle performance.
Maintaining proper tire pressure is essential for the safety and performance of a vehicle. It also plays a significant role in decreasing fuel consumption and extending tire life.
All tires lose inflation over time and, as many modern vehicles have extended service intervals, tires can become dangerously under-inflated without regular checking by the vehicle driver.
In addition to increased fuel consumption and tire wear, long periods of driving with low tire pressures can cause additional stress on the tire sidewalls. This results in increased operating temperatures that can lead to premature tire failure.
Tires operating with low pressures can also affect the vehicle's handling and performance. In a worst-case scenario, under-inflation can lead to a tire blowout or tread separation.
Automated Tire Pressure Monitoring Systems or TPMS provide a means of reliable and continuous monitoring of the vehicle tire pressure and are designed to increase safety, decrease fuel consumption and improve vehicle performance.
TPMS is an automated system that monitors the air pressure in a vehicle's tires. When air pressure in one or more tires drops 25 percent or more below the correct pressure, a warning indicator alerts the driver. TPMS typically delivers these alerts to the driver through one of two types of warning lights on the dashboard.
 1. The first uses the official TPMS symbol, which is a cross-section of a tire with an exclamation mark in the center.
2. The second is a top-view graphic image of a car that indicates which tires are low.
Tire pressure is monitored through one of two methods: direct or indirect.
Direct TPMS monitors the actual air pressure inside each tire via a sensor mounted within the tire.
Real-time information is sent via wireless signal to a display in the vehicle. If a fluctuation occurs, an audible and visual warning instantly alerts the driver allowing time for the vehicle to be stopped or driven to a service station for tire repair or re-inflation. The tire is used to enclose the unit as protection from the outside environment. An on-board computer receives the radio messages from the sensors, which are coded for individual wheel identification.
The interactive display inside the vehicle shows:
• The required tire pressure
• the actual tire pressure
• the tire pressure status
• and the temperature of the tire
Indirect TPMS measures tire pressure by monitoring the speed and rotation of each individual wheel.
When a significant variation in speed and rotation is detected in one or more wheels when compared with the others, it is often an indication of underinflation. This information is then transmitted to the vehicle's on-board computer, and the driver is alerted.
With a Tire Pressure Monitoring System installed on a vehicle, drivers can monitor the tire pressures and temperatures from the driver's seat to ensure that their tires are properly inflated under all operating conditions. The systems are also designed to ignore normal pressure variations caused by changes in ambient temperature.
The sensors are activated by a centrifugal switch and transmit only when the vehicle is in motion. When the vehicle stops the sensors return to sleep mode to extend battery life, however the driver is still able to review the latest signals received from the wheels before the vehicle was stopped.
Even though TPMS has only recently become standard for all vehicles, a number of older models already have them installed. Approximately 20 percent of 2006 vehicle models came pre-equipped with TPMS, and that number increased to 70 percent in the 2007 model year.
If you are unaware if your vehicle has TPMS installed, check your vehicle owner's manual. If you don't presently have TPMS on your vehicle, we can help. |
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1. An Introduction to Wheels and Tires
2. Tires
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4. Manipulating The System
5. Valves
7. Tire Inspection
8. Tire Wear Guide
9. Tire Rotation
10. Wheel Assembly
11. Wheel And Rim Construction
Hot Topics
-> 4 Things You Can Start Doing Today To Extend The Life Of Your Tires
-> New Tires Guide
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-> What Does It Mean When My Wheels Are Imbalanced?
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