1. What size is my tire? The size of your tire can usually be found on at least six places on your car: on each of the tires, on the driver's side door jam, and in your owner's manual. Normally the front and rear tires are the same size, but on some exotic sports cars the rear tires may be different than the front. Unless specified otherwise in the owners manual you should always try to keep all four tires identical.

2. How do you read the sidewall of a tire? On the side of your tire you'll find the size, make, and model of the tire, along with its maximum inflation and load, speed rating, and safety warnings. Sizing on today's vehicles usually looks like this:

P235/75R15 105S (cars) or
LT235/75R15 104/101Q (trucks)

3. Can I downgrade the speed rating of my tire? We do not recommend using a tire with a speed rating lower than that which the vehicle manufacturer recommends for your car. Many people may try to downgrade to save themselves a few dollars, but this is penny-wise and pound-foolish. By downgrading the speed rating of your tires, you will reduce the vehicle's handling and your control in emergency situations. The $50 you save yourself by downgrading won't cover the cost of the tow when you find yourself in a ditch. The industry accepted exception to this rule is that you may downgrade one speed rating level when switching over to snow tires. The bottom line is if you want your Geo to handle like a BMW, upgrade the speed rating. If you want your BMW to handle like a Geo...

4. What does UTQG mean? UTQG stands for the Uniform Tire Quality Grades, which the Government requires on all passenger car tires. The UTQG has three components: a treadwear rating, a traction rating, and a temperature rating. This rating system was developed many years ago so consumers could compare the different qualities of various tires. A standard test tire was chosen and all passenger tires since have been judged against this standard. Tires today tipically have treadwear ratings of 200 to 600 (the standard tire was 100), a traction rating of "A" or "B" (on a scale of AA, A, B, and C), and a temperature rating of "A", "B", or "C" to gauge a tire's resistance to heat buildup. Unfortunately, this rating system is now nearly useless as a comparative tool because the tire manufacturers perform the tests without much oversight from the government. The ratings can be useful to compare tires made by the same manufacturer, but is less useful when comparing a Goodyear to a Michelin. Furthermore, there are virtually no "AA" or "C" rated traction tires, so most of the tires are "A" with a few "B" rated tires near the low end.

5. Which tire is the right one for my car? Selecting the right tire for your car is part art, part science. Before we suggest a tire we like to ask a few questions about the driver such as:

We're here to help you choose the right tires for your vehicle. Just call Harper's Tire.

6. Should I buy four tires or two? All of the tire manufacturers and vehicle manufacturers recommend replacing tires in sets of four. Honest, this isn't just some sales ploy. Check your vehicle's owner's manual if you don't believe us. Here's why. When all four tires on the vehicle are identical they act like a synchronized swimming team, all cornering, handling, and tracking the same. When you break up the team, there's chaos at the four corners of your vehicle, resulting in poorer performance and handling which could jeopardize your safety. This is especially true when it comes to snow tires. Today's snow tires behave so radically different than conventional all season tires that a vehicle can easily become unstable if you mix the two tire types.

7. If I buy just one or two tires, where should they go? In the real world many people end up replacing just one or two tires at a time for a variety of reasons. When you are replacing only two tires, make sure the replacement tires are of the same size and construction as those on the car, and preferably identical to the two remaining tires. Furthermore, for safety reasons we recommend you put them on the rear axle, even on front wheel drive cars. If you are only buying one new tire, it should be paired on the rear axle with the tire having the most tread depth of the other three.

8. Should I buy two or four winter tires? Today's snow tires behave so radically different than conventional all season tires that in a situation where the road surface changes (like on icy or snow covered roads), the vehicle can become unstable and start to fishtail or spin out. This situation is commonly referred to as Oversteer. For more info go to http://www.cbc.ca/marketplace/get_a_grip/

9. What does the Mountain/Snowflake symbol mean? The Mountain/Snowflake symbol is a new designation that indicates that a tire has been approved for use in severe winter conditions. The symbol, just recently approved by the Rubber Manufacturers Association, will be phased into use over the next three years. Most of this year's crop of snow tires don't yet show it on the tires sidewall, but look for the symbol as you're surfing the manufacturer's sites to determine which tires are the best for winter use.

10. How much air should I put in my tires and how often should they be checked?  Harper's Tire recommends you inflate your tires to the pressure designated by your vehicle's manufacturer. You can find this information in your vehicle's owner's manual or sometimes on the driver's side door jam. The maximum air pressure stamped on a tire may be used under certain circumstances such as when you are carrying a heavy load, driving in extreme heat, or pulling a trailer.

You should check the inflation pressure of your tires, including the spare, at least once a month and always before extended driving. Check the pressure when your tires are cold; that is, when your vehicle has been parked for at least three hours. If necessary, add air to inflate your tires to the pressure specified on the vehicle placard. Since this reading will be most accurate with cold tires, drive to the nearest source of pressurized air whenever possible. Never "bleed" or reduce the inflation pressure when your tires are hot. When tires heat up from driving, it is normal for inflation pressures to increase above recommended cold inflation pressure levels. If you let air out of a hot tire, it will be under-inflated when it cools down.

Also use a high quality air pressure gauge to check your tires. Don't trust your eyes. You can't tell by looking at a tire if it is properly inflated.

11. How often should I rotate my tires? The purpose of regular rotations is to achieve more uniform wear for all tires on the vehicle. Your tires should be rotated every 10,000 kilometres or at any sign of uneven wear. If your tires show uneven wear, have a service person check and correct any misalignment, imbalance, or other mechanical problems.

12. What is wheel balancing and how is this different from wheel alignment? A wheel that is out of balance is like a washing machine that has too heavy of a load to one side. The centripetal force created by the spinning of the laundry basket combined with the heavy load off to one side causes the washing machine to bounce around and make an awful racket. The same thing happens to a car's tire if it is out of balance by as little as a quarter ounce. The tire and wheel assembly tends to hop around and cause a vibration. This vibration is usually felt on expressways where the higher driving speeds accentuate the shaking. If the vibration is in the steering wheel chances are the tire that needs balancing is on the front axle. If the vibration seems to be coming from all over, the problem tire is probably on the rear. This problem can be cured simply by using a computer spin balancer to attach weights to the outside lip of the wheel.

Wheel alignment has nothing to do with wheel balancing. A vehicle's wheel alignment determines whether the vehicle will track straight down the road, and, if it is out of alignment, will cause the vehicle's tires to wear prematurely or with a funky pattern that may create a lot of noise. You should have your vehicle aligned annually or whenever it starts to pull or drift to the right or left.

13. How long will my tires last? The average tire today lasts around 60,000 km's, but like anything else, you get what you pay for. Many are capable of much longer mileage with treadwear warranties at 100,000 km's or higher. Others, such as performance tires, are designed to maximize their cornering and handling capabilities at the expense of treadlife and may wear out as quickly as 30,000 km's. Other factors such as how you drive (easy or hard), where you live (flat or hilly), and road surface (concrete vs. asphalt) will also strongly affect the longevity of your tires.

14. How can I tell if my tires are worn out?  Harper's Tire recommends that you replace your tires when they are worn out. A tire is considered no longer usable when the tread depth is at 2/32nds of an inch or less. Tires have treadwear indicator bars within the tread channels that are 2/32nds of an inch high. If these indicators are flush with the surface of the tire then your tire is legally bald. However, you may experience a loss of traction well before the tire is completely worn out. If you live in a climate where rain or snow is an issue, you may find it necessary to replace your tires even though they still have 4 or 5/32nds of an inch worth of tread on the tire. If you're in doubt, feel free to call or stop by the store and speak with one of our Tire Experts. And remember the only safety features on your car that is touching the ground are your tires. Now let's be careful out there.

15. I have a flat tire, what should I do? If you have a flat tire, pull to the side of the road. If you're on a busy or narrow road, drive slowly to a place where you can safely get out of the car. If you know how to change a flat tire, then do so, otherwise find a phone and call a local tow truck company for assistance. Clean punctures in the tread area of a tire may be professionally repaired using the industry standard procedures recommended by the Rubber Manufacturers Association's Technical Publication Number 19. A punctured tire must be dismounted and inspected for signs of internal damage. Do not use plug repairs; they are dangerous and may void the manufacturer's warranty. Also, do not use an inner tube for the repair of a damaged tire.

A damaged tire is not repairable and should be replaced if:

16. Why do tires blow out? No manufacturer has created the perfect tire yet, so unfortunately tires do blow out. There are many reasons a tire can blow out. Usually it is caused from a foreign object impacting the tire, thus causing a sudden loss in air pressure. Sometimes a foreign object impacts a tire and causes a slow loss of air pressure which cannot always be detected by the driver. A tire driven while low on pressure loses its ability to dissipate heat. This heat can cause a thermal breakdown of the tire on a molecular level, resulting in a blowout. Under these circumstances it is often impossible to determine the actual cause of pressure loss. A tire can also blow out due to an impact it received sometime in the past. An impact break can happen when a tire impacts a pothole or rut in the road. This impact break can be small at first but grow over time and thus eventually cause a blow out. This is often noticeable as a slight bulge in the sidewall of the tire. So remember when you think, "Well, I didn't hit anything!", it may be caused by a previous injury to the tire.

17. Can changing tire sizes confuse my vehicle's on-board computers? It can if you substantially change the overall diameter of your tires. Maintaining the original, specified diameters as closely as possible ensures that your on-board computers will function properly and thereby effectively manage such systems as your anti-lock braking system, traction control, fuel management system, electronically controlled automatic transmission and electronic handling stability system. Changing tire diameters sends erroneous readings to the computers. These systems won't fail, but they will be impacted to varying degrees.

18. Should I be concerned about tire load carrying capacity? A replacement tire must always meet or exceed the load carrying capacity of the original. If you replace original equipment tires with the same size and type replacement tires, your newest tires will be able to handle the weight of your vehicle and its maximum allowable load.

19. What might happen if I run my tires under-inflated, or over-inflated? Under inflation can cause extreme sidewall flexing. The result may be dangerous heat build-up that can lead to premature tire failure. Over-inflation can cause your tires to be more susceptible to impact damage. Either condition may adversely affect vehicle handling and treadwear.

20. What's the difference between an all-season and an all-terrain type tire? An all-season tire is designed with a long lasting, aggressive tread pattern designed to get rid of water and snow, balancing the wet and snow traction capabilities with dry pavement performance. They generally feature lots of biting edges that enhance snow and wet traction. Most tires with these features are branded M&S for mud and snow. An all-terrain type tire is a light truck tire that has been designed with an even more aggressive tread pattern. This type of tire may be driven on or off the road in virtually any type of weather and road condition. In rain and on mud, an all-terrain tire's open, self cleaning tread provides excellent traction, and it's rugged edges grip on rocky and uneven terrain.