January 9, 2015
Most vehicle today have some form of Tire Pressure Monitoring.  Basically there are two types of systems in use today: In-Tire Pressure Sensors The first type is one whereby each wheel has an individual tire pressure sensor installed directly inside each wheel.  It is either strapped around the center of the rim or it take place of the traditional rubber valve stem that is utilized to add air to your tire.  These types of sensors are battery operated and for this reason, do not last forever.  When the battery fails, the sensor requires replacement.  In order to replace the sensor, Car Medics in Kingston ON or Glenburnie On will need to remove your tire from the vehicle, remove the tire from the rim and install a new sensor.  This sensor, just like a new TV remote control, has to be programmed in order to be recognized by your vehicle.  Each sensor has an individual RF (radio frequency) similar to a cell phone.  Once this new sensor is added, your car will then begin to monitor tire pressure along with the other wheels. The advantage of these sensors is that they “directly” measure the tire pressure within each wheel.  Often they can even broadcast tire temperature.  The reason for this is that tire temperature is critical as a tire gets low in pressure and it is this temperature rise that leads to catastrophic tire failure. Most often, your vehicle will set off an alarm when either a tire gets too low (often below 27-28 psi), gets too hot (often over 85C) and one tire begins losing are at a rapid rate. The advantage of this type of system is that it tends to be very accurate, often displaying the tire pressures directly on the dash or customer information center. The disadvantage of these in-tire sensors is the added cost when you install another set of rims and tires for winter driving.  You must purchase another set of 4 tire pressure sensors for this second set of rims and then have them “programmed” by a professional, such as the certified technicians at Car Medics ON, in order to keep the TPMS system functioning correctly regardless of which set of tires/rims are installed. If a vehicle owner decides to drive on winter rims/tires where there are no TPMS sensors installed on a vehicle that requires them, the additional safety of the TPMS system will be rendered disabled.  In the view of Car Medics, most people would rather be warned or prevent a low or flat tire during the winter months as this is the worst time to be disabled at the side of the road. Examples of vehicles that employ the use of in-tire tire pressure sensors: Honda, Toyota, Acura, Lexus, Subaru, Nissan, GM, Ford, Chrysler and many others.   Tire Monitoring Using ABS System (Anti-Lock Braking System) This type of tire pressure monitoring system does not use any in-tire pressure sensors and the tire pressures are not measured directly.  Rather, the vehicle uses the ABS system to monitor the rotational speed of each wheel. It uses this individual wheel speed to “calculate” tire pressure “changes” and sometimes even calculates the projected tire pressures as well. ABS, or Anti-Lock Braking Systems, basically utilize a special speed sensor located behind each wheel and/or on each axle.  With this information, your vehicle can tell if one or more wheels are speeding up and/or slowing down faster than the rest.  It can then apply or release the brakes as needed to prevent the wheels from skidding and/or slipping.  As each wheel rotates, the exact speed of each wheel is even more closely monitored so that even very subtle changes in wheel speed can identify a tire that is going flat or is flat.  The key to this is the fact that a tire will expand and contract with changes in tire pressure and a tire that loses air, will tend to become smaller.  When the tire becomes smaller, it will rotate more times for the same distance traveled by the other wheels, resulting in that affected tire “speeding” up.  The TPMS / ABS computer can translate these very slight changes into low tire warnings. The advantage of this type of TPMS system is the elimination of costly tire pressure sensors and their maintenance.  In fact, some car makers are now eliminating in-tire sensors altogether and are changing their systems to the ABS /wheel speed monitoring system for low tire conditions. The other advantage to this type of tire monitoring is that you will not need to purchase tire pressure sensors should you decide to install another set of tires and rims for winter driving. The disadvantage of this type of system is that occasionally the system needs to be reset when you add air to your tires, have them rotated or you suddenly change the amount of weight the vehicle is carrying. Examples of vehicles that use their ABS system to monitor for low tire conditions: BMW, Mini, Hyundai, Kia and many others.   Conclusion If you live in or around the Kingston, Ontario / Glenburnie, Ontario area, and you have any issues with low tires, flat tires and/or TPMS warning lamps illuminated on your dash, bring your car to Car Medics.  We have one location in Kingston, ON on Rigney St. and another location at 1985 Perth Rd., Glenburnie, Ontario.  (Our Glenburnie location was formerly Jack Bowes Auto Service.)



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