Understanding your Tires

For example, the number may read P225/70-R15, 89H:

  • P = Passenger Tire (LT = Light Truck)
  • 225 = Overall width of the tire in millimeters
  • 70 = Sidewall height (distance from rim to tread) as a percentage of the thread width (known as aspect ratio)
  • R = Tire construction, this one is Radial (also, B = Belted Bias, D = Diagonal Bias
  • 15 = Represents the size of the wheel in inches
  • In this example, the tire has the number 89H. This is the weight capacity of the tire. However, in most cases, you will not see this heading on the sidewall.
  • A speed rating is sometimes put in front of the R (or B or D). A straight R rating means that it is rated for speeds of up to 100mph. The manufacturer does not recommended this tire for speeds greater than 100 mph. Other speed ratings are: S=112mph, T=118mph, U=124mph, H=130mph, V=149mph, & a Z rated tire is for speeds in excess of 149mph.
  • The V and Z rated tires have excellent dry pavement grip/traction but due to their soft rubber compounds, do not have a long life.
  • A tread rating indicates how long a tire should last. This figure is written in small letters on the sidewall of your tire. The higher the number, the longer the tire should last. 100 is the basic tread wear rating.
  • The traction rating works just like grading – ‘A’ being the best, ‘B’ is good, and ‘C’ is acceptable. This number is also found on the sidewall.
  • Temperature ratings work the same – ‘A’ best, ‘B’ good, ‘C’ acceptable. If you drive your car very hard, you want a temperature rating of ‘A’ because a ‘C’ would fail faster under these conditions. Again, look for this number on the sidewall
Nitrogen Inflation

Nitrogen inflation is now available at all Auto Magic Service Centers in Prince George.

Nitrogen inflation is unique from traditional compressed air inflation in several ways. First, Nitrogen maintains a tire’s inflation pressure longer than compressed air. This stability is possible because Nitrogen consists of larger molecules that do not seep out of a tire as quickly as compressed air. Proper inflation reduces a tire’s rolling resistance, which improves gas mileage, and increases tire life.

Second, Nitrogen allows tires to run cooler. Under inflated tires flex and bend more when rolling. This additional movement generates heat. Heat is a tire’s worst enemy because it accelerates tire wear. Nitrogen seeps less than compressed air, so it is less likely to cause under inflation.

Nitrogen inflated tires also run cooler because it is an inert gas. The air inside a tire expands when heated and contracts when cooled. Typically, one p.s.i. (pound per square inch) is lost for every ten degree change in temperature. Being inert means that Nitrogen will fluctuate less despite temperature changes producing more stable inflation pressures.

Third, Nitrogen causes less oxidation and reduced rim and wheel corrosion than compressed air. Compressed air comprises of 78% Nitrogen, 21% Oxygen, 0.9% Argon and 0.1% miscellaneous gases. Compressed air also contains moisture that reacts with and deteriorates rubber while corroding rims and wheels. This damage causes air to seep from a tire more quickly making it very difficult to maintain appropriate inflation pressures.

Nitrogen avoids several of compressed air’s disadvantages. Its ability to maintain inflation pressures longer over time results in extended tire life, improved fuel economy and reduced tire aging. Extended tire life and improved fuel economy reduce vehicle operating expenses for drivers.


What is an alignment?
It’s just the angles of the front suspension and front tires. You want the four wheels to go down the road in the same direction. You want them going straight.

Why is proper alignment important?
To prevent tire wear and for road stability.

When should alignment be checked?
We recommend once a year, unless you hit a pothole, or run over a raccoon, or bounce off a curb. People who drive on gravel might need to check more often. For cars driven only on highways, usually a check every two years is enough.

How do you know when you need an alignment?
Normally, if it’s bad enough, it either pulls one direction or the other, or the steering wheel is crooked. The car might wander on the road and might not hold a straight line as well.

If the car ride is bumpy, is the car out of alignment?
Bumpy is more of a tire problem.

Check alignment, as detailed above.

  • Check for wear and damage.
  • Check tread depth. Measure the tread using a penny to check that tire tread is at least as deep as the distance between the edge of the penny and the top of Queens head (about l/16 inch). Seventy-five percent of the problems with tires occur in the last 25% of tread wear.
  • Check for nicks or cuts in sidewalls, as they are especially dangerous.
  • Avoid cupping, or irregular wear along tire shoulder edges

Rotate tires every 10,000 to 15,000 kilo meters, or according to the owner’s manual. Tires do not wear evenly unless they are rotated. Rotation extends the life of the tires.


Feeling vibration while driving may indicate the tires are out of balance. At high speeds, improper balance can ruin a tire and cause damage to the suspension.

Spare Tire

Keep the spare tire properly inflated and in good condition. Check that the jack is in proper working order.

Driving for Best Wear
  • Smooth driving prolongs tire life, while improving gas mileage and allowing safer handling. Avoid cornering at high speeds and squealing tires, for instance.
  • Sudden stops are hard on tires. Driving in stop and go traffic can wear tire tread seven times faster than steady driving.
  • Excessive highway speed can build up tire heat, which deteriorates rubber and accelerates tire wear.
  • If potholes or rough roads are unavoidable, check alignment.
  • Tires are rated for weight-carrying capacity; overloaded tires wear faster.
Buying Tires
  • Replace tires with the right size and type for the vehicle.
  • Most tires offer mileage specifications. Compare new tire life expectancy to the tire price, to choose the best value. Ask questions.
  • Proper disposal of used tires is handled by retailers for a small recycling fee at time of purchase.
Pricing & Policy

Auto Magic always emphasized honesty, integrity, service, value for each customer’s money and the best interests of the customer. We believe that adherence to these five principals would guard the reputation of the business, and best serve our customers.

For example, we do not sell products to people who don’t need them. When people come in who don’t need tires, they are sent away and asked to come back later.

Customer Service

Service and experience are important components of the product at Auto Magic. The present staff has amassed over 200 years of experience in the tire business.

Whether driving down highway 97 or 16 at high speeds, or navigating icy roads, only your tires touch the road. Safety, of course, is paramount. Buying tires should not be like buying fast food.

As they head into their fifth decade, Auto Magic remains a supplier that knows about tires, knows how to maintain them properly, how to diagnose a vehicle’s needs and to choose the product appropriate for each special situation. They are there to care for those needs year after year. Because of their focus on safety and service, the experienced personnel at Auto Magic sell tires, but supply driver confidence at no extra charge.

Tire & Wheel Brands


BF Goodrich


American Eagle
American Racing
US Wheel

And more… call us!