I decided to re-post this here as well as in the Tire Rack vendor thread, as there are so many questions on this topic.
Maintaining the correct tire pressure for a vehicle is an important factor in how much load its tires can safely carry. The correct pressure will carry the weight without a problem. Too little tire pressure will eventually cause catastrophic tire failure.
Tires aren't invincible. They are made of individual layers of fabric and steel encased in rubber. If a tire is allowed to run low on air pressure, the rubber is forced to stretch beyond the elastic limits of the fabric and steel reinforcing cords. When this happens, the bond between the various materials can weaken. If this is allowed to continue, it will eventually break the bonds between the various materials and cause the tire to fail. And even if the tire doesn't fail immediately, once a tire is weakened it won't heal after being reinflated to the proper pressure. So if a tire has been allowed to run nearly flat for a period of time, the tire should be replaced, not simply repaired or reinflated.
Try flexing a piece of sheet metal back and forth and you may get to 30 or 40 times before it fractures.. Somewhat like that piece of sheet metal, your tire, when run low on air can rip at the weakest point. A typical 18” tire may revolve 750-800 times per mile! On a 20 minute trip at highway speeds the underinflated tire may needlessly overflex as many as 16 thousand times.
But I checked my tire pressure yesterday morning!?! Yes. And you ran over that nail yesterday afternoon. We all know how quickly (or slowly) a tire can lose pressure. Even I don’t check my tire pressure every day. I try to do it on the first of every month. So you can see how long you might drive on an underinflated tire before you catch it or it catches you.
TPMS or Tire Pressure Monitoring Systems are the electronic watchdog for your tires (and your) well being.
Split up into 2 groups: Direct and Indirect, I will talk only about the Direct systems as these are what are used on
Chrysler Corp vehicles.
Some systems indicate which tire is low and may even monitor your spare, while others only alert you that one of your tires is low.
Each wheel has a small sensor that is part of the wheels valve stem. The sensor, about the size of a box of matches is on the back side, inside the tire and wheel assembly.
Each of your sensors is a small radio transmitter. It lays dormant (park mode) when the car is at rest. The sensor then wakes up when the car travels at 15mph. If the car comes to rest for 20 minutes or more the sensors shut down again to park mode. This extends the life the batteries, which should last a number of years. (7-10)
If the pressure exceeds the high or low limits of the pressure threshold, the sensor sends a signal to the system receiver and your warning indicator illuminates.
If a system fault occurs the indicator light will flash on/off for 60 seconds, once every 10 minutes.
TPMS systems may not react instantaneously. If you have major tire injury you may find yourself pulling to the side of the road before, or just as, the TPMS light alerts you.
Your existing sensors can be installed into your new set of wheels before the tires are mounted. You will have to have your old tires dismounted from your OE wheels in order to remove the sensors.
If you choose to purchase a new set of wheels and do not install the new TPMS sensors you can expect to see the yellow warning indicator lamp illuminated all the time.
If your state does annual auto inspections it is a good idea to ask if you will pass inspection without TPMS working properly.
Check your owner’s manual for information on the reset, initialize, re-learn procedures.
For Chrysler Corp. vehicles this usually consists only of driving at a given speed for a number of minutes. Sometimes this is more involved depending on the system.
Even when TPMS systems are employed you should still check your tires pressure on a regular basis.
Linear Mode
