Frequently asked questions
Why can't I use only two winter tires?
If you were to put winter tires on only the front or rear of your vehicle, you would create a vehicle with a split personality.
When should I mount winter tires on my vehicle?
It is recommended to mount winter tires as soon as the temperature remains consistently near freezing.
How is the overall tire diameter measured?
A tire is mounted on the appropriate rim width as identified by T&RA (Tire & Rim Association) or ETRTO (European Technical Rim & Tire Organization) then inflated to 26 psi. A calibrated measurement tape if run around the circumference of the tire in the center of the tread (which represents the largest overall diameter). This measurement of circumference is then divided by the mathematical constant known as PI (3.14126...) to calculate diameter.
What is the proper air pressure for my tire?
Proper air pressure for a tire is determined by the vehicle manufacturers and is set to best fine-tune a tire's capabilities to their specific vehicle make and model. The vehicle manufacturer's pressure recommendation can be found on the vehicle's tire information placard label, as well as in the vehicle owner's manua.
Can I go to a lower speed rated tire than what came on my vehicle?
It is recommended that the replacement tire size speed rating be equal to the O.E. tire size speed rating. If a lower speed rated tire is selected, then the vehicle top speed becomes limited to that of the lower speed rating selected. It is quite common and permissible during winter driving to use a winter tire with a lesser speed rating that the O.E. tire.
What guidelines should I follow when mixing tires on 4WD vehicles?
If no instructions for the tire mixing appear in the vehicle owner's manual, adhere to the following guidelines:
What is the difference between P-Metric and Metric?
P-Metric sized tires are those with the "P" at the beginning of the tire size (such as P215/65/16). P-Metric sizes were introduced in the United States in the late 1970's and are installed on vehicles primarily used to carry passengers including cars, station wagons, sport utility vehicles and even light duty pickup trucks. Their load capasity is based on an engineering formula which takes into account their physical size (the volume of space for air inside the tire) and the amount of air pressure (how tightly the air molecules are compressed). Since all P-Metric sizes are based on the formula for load, vehicle manufacturers can design their new vehicles (weight and wheelwell dimensions) around either existing or new tires.