The winter possesses a unique set of challenges for drivers. Snow, rain and ice often coalesce into a challenging drive for commuters. Vehicle tires undergo tremendous stress during changing weather conditions. During periods of extreme temperature fluctuations (up or down), tire pressure can fluctuate enough to signal-on the tire pressure light in newer vehicles. Additionally, incorrect tire pressure can lower fuel economy, make a vehicle more susceptible to damage from potholes, impact vehicle handling, and cause tires to wear quickly and/or unevenly.
ALTERNATING TIRE PRESSURE
Changing weather conditions attributes to the measurement of pressure in your tires. Hot weather or a long road trip will increase tire pressure. However, very cold weather can cause your tire pressure to deviate from the recommended inflation pressure, activating the TPMS (Tire Pressure Monitoring System)* in newer vehicles. Most TPMS monitor under-inflation as it poses a greater risk while driving. Tires will wear unevenly on the inner or outer most edges of the tire. An under-inflated tire is not only noisier, it creates more frictional heat, and, therefore, more prone to blowouts. Furthermore, an under-inflated tire can cause costly damage to your vehicle during the pot-hole season. The tire will have difficulty absorbing the impact from potholes which can cause damage to rims, or worse.
Tire pressure changes while sitting overnight or during a long commute to work. Pressure can change by up to 5-psi from a 20-30 minute drive vs when parked overnight. Additionally, if the outside air temperature decreases by 5.5 degrees Celsius, the tire pressure will fall 1-psi. Conversely, if the air temperature increases 5.5 degrees Celsius, the tire pressure will rise by 1-psi.
It is recommended to check tire pressure at least once a month for all tires on your vehicle. It is important to note that you should only add or release air from your tires, after your vehicle has been sitting for several hours.
*Many newer vehicles (beyond 2008) have a tire pressure sensor that constantly measures the inflation of each tire.
TIRE PRESSURE & FUEL ECONOMY
Generally, the acceptable tire pressure range is between 30-35 PSI. Automotive manufacturers have different pressure specifications, designed to provide the maximum performance based on the vehicle. Refer to the gas tank cover or drivers-side door panel to find a vehicles recommended tire pressure. On the side-wall of a vehicle tire, the maximum allowed pressure is shown. It’s important to note this number is the maximum pressure the tire can operate at during full load. This number is not the pressure rating your tire should be inflated to.
Fuel economy will be impacted by improper tire inflation. The U.S. Department of Energy says that for every 1-psi drop in pressure, you can expect your gas mileage to lower by 0.4 percent. Inflating a tire beyond what is recommended from the vehicle manufacturer can improve fuel economy. Doing so can sacrifice handling and comfort; the vehicle will ride harshly over imperfections in the road. Additionally, the center thread of tire will wear quicker.
TIP: before towing a trailer, or a load of people add a couple PSI to the back wheels. Refer to your vehicle to see the recommended “at load” pressure.
CHECKING TIRE PRESSURE
Pick-up a standard or digital tire pressure gauge. In the morning, or before a long drive remove the cap from valve stem. Measure the PSI of pressure by firmly pushing the gauge to the vale stem. Ensure there is no air leak between the nipple and gauge to collect an accurate reading.