Tyre Tips

Answer : Before you decide on a new tyre, ask yourself these questions:

• What tyres are on your car now?
• Did you like your old tyres? (Smooth ride, good handling, long wearing, etc.?)
• What do you want your new tyres to do?
• How important is crisp handling and quick stopping compared to smooth ride or long wear?
• What kind of “look” are you after?
• What level of convenience, service and warranties do you expect?

When you answer these questions, you narrow the choices to ones that fit your specific needs and wants.

Determining your correct tyre size

Look in your automobile owner’s manual. You’ll find the size fitted on the car originally. Unless you’ve changed wheels, that’s the recommended size. The tyre size is written on the tyre’s sidewall.

Example – Tire sizing as it appears on the sidewall:
215/65R15 89H
215 — Width of tire in millimeters
65 — Ratio of height to width (aspect ratio)
R — Radial
15 — Diameter of wheel in inches
89H —Load index & Speed Symbol

Reading the tire sidewall

Width of the tire in millimeters: The higher the number the wider the tyre. Aspect Ratio: The height of the sidewall section compared to the width of the tyre.

Example – If this number was a 50, then the tyre section is half as tall as it is wide.

Short sidewalls deliver crisp handling. Tall sidewalls give a smoother ride. For a specific tyre width, the smaller this number, the shorter the sidewall.

Construction

“R” indicates radial construction. Unless you specify the other option, bias (which would have a “D” (diagonal) or “B” (belted bias) in this position instead of an “R”), you are purchasing a radial tyre.

Wheel size designation

This indicates the distance across the “doughnut hole” of a yire in simple terms. You must match wheel diameter and the tyre opening. A tyre with a 15 size designation will not work on a 14” wheel, and vice versa. Improperly matching of wheel and tire size can cause serious injury or death during installation.

Service description

Includes the load index (a number) and a speed symbol (a letter). About load index, remember: keep the number the same as or greater than the original tyres’ load index. That number stands for a specific weight carrying capability. Key is that the higher the number, the greater load carrying capacity. So keep the number the same or higher, because your tyres are matched to the weight of your car. Never choose a tyre with a lower load carrying capacity than the original equipment tyre size.

Now the speed symbol Each letter corresponds to a speed rating on an indoor test wheel:

• N = 140 km/h
• P = 150 km/h
• Q = 160 km/h
• R = 170 km/h
• S = 180 km/h
• T = 190 km/h
• H = 210 km/h
• V = 240 km/h
• Z = 240+ km/h
• W = 270 km/h
• Y = 300 km/h

We recommend that the replacement tyres match the speed symbol of the original tyres since these match the speed capability of the vehicle.

Uniform Tyre Grading (UTQG)

The Uniform Tyre Quality Grading (UTQG) is a system developed to help consumers compare tyres in the areas of treadwear traction and temperature. Example – A tyre with a UTQG of 300 AB: The 300 is treadwear, which represents the tyre’s comparative wear when measured against the government-mandated tyre which is rated at 100. So this tyre wore three times longer than the control tyre.

Because of variations in operation conditions, the treadwear grade cannot be used to predict actual wearout mileage. It can be used to predict the relative wear rate of tyres with different UTQG wear rates.

Traction and temperature are graded A (superior), B (good), or C (average). Traction indicates the level of grip the tyre possesses. Temperature rating deals with the tyre’s ability to disperse built-up heat. Heat causes rubber to deteriorate over time, so dispersing heat increases tyre life.

Each tyre manufacturer determines UTQG rating for their products. Realise that UTQG’s are more accurate when comparing tyres within the same line versus tyres from two different makers.

Pressure

It is important to have the proper air pressure in your tyres, as under inflation is the leading cause of tyre failure. The right amount is specified by your vehicle manufacturer and is also listed in your owner’s manual.

Alignment Misalignment of wheels in the front or rear can cause uneven and rapid treadwear. Have your alignment checked periodically.

Rotation

Sometimes irregular wear can be corrected by rotating your tyres. Consult your vehicle owner’s manual or your tyre dealer for the appropriate rotation pattern for your vehicle.

Tread

Tires must be replaced when the tread is worn down to 1.5mm (min WOF level) in order to prevent skidding and hydroplaning.

Answer : Here are 6 simple safety checks and safe driving tips to save money on tyres

Safety Check #1. Depth of tread.

When was the last time you measured the tread on your tyres? There are legal requirements for the amount of tread on the tyre. Why? More tread equals better grip of the road, which equals safer driving for you. Tyres that are worn are not safe for you or for other drivers. Bald or worn tyres lead to lack of control when steering or braking.

Safety Check #2. Check the side walls.

If there are cuts or gouges in the tyre walls consider replacements. It is possible to repair small punctures in the tyre walls but it depends on the size and location of the damage. Often it’s best to replace the tyre. Would you want to risk a sudden failure at high speed?

Safety Check #3. Check the tyres' pressure.

Check the pressure when the tyres are cold. The pressure inside your tyres changes as you drive. Although air inside the tyre expands as it heats up, low pressure may be more risky than slightly higher pressure. It exposes tyres to greater wear and they will need replacing sooner. Soft tyres use more fuel, hurting your pocket. At the same time avoid over-inflating.

Safety Check #4. Avoid potholes and curbs.

Have you noticed how many holes there are in the roads you normally travel? Tyres take all the impact when you hit one of those holes. There is a danger of sudden loss of air in the tyre leading to possible loss of control and maybe an accident. The same applies if a wheel hits the curb. Watch for holes in the road and take care when parking. You will save money in the long run.

Safety Check #5. Are you balanced?

Does the steering wheel vibrate when you drive? This may mean your wheels need to be balanced. Balancing is essential when you buy a new tyre. This may be included in your purchase price or a separate charge, but don’t overlook it. Unbalanced wheels impair steering, and increase wear on your vehicle’s suspension system.

Safety Check #6. Loading weight.

Excessive or incorrect loading could be more than your tyres can bear. Too much weight can cause the tyre to come off the rim when cornering, putting you and your passengers at risk. Don't put passenger car tyres on trucks either, they are not made to take the weight, so it’s a false economy, as you will have to buy another set almost immediately.

Ask your preferred tyre dealer to inspect your tyres at least twice a year. Likely there’ll be no charge for this service, but it doesn’t hurt to ask first.

Answer : Rotation can increase your tyre life Tires subject to regular rotation can last up to 20% longer rotation Rotate your tyres for longer life. The life I'm talking about is YOURS, not your tyre's.

Even though tyre dealers will frequently offer free rotation for their customers, this is a benefit which is far under used. I know that the dealer is offering this free benefit because they hope to get extra business from the problems which generally become obvious if tyres are inspected regularly.

I think that most people avoid this free service because they don't like the surprise of being told that they need to pay for some service that they didn't know they needed and they mistakenly believe that what they loose in shorter tyre life is made up by lower repair costs on their car.

This may be true, but because tyres are the only things which allow you to safely control your vehicle, I consider the risk of having a dangerous tyre defect remaining undetected as too high a price to pay for saving a few dollars on maintenance.

In the end, this is something you'll have to decide for yourself, but be informed so that you at least know what risks you are taking if you choose to ignore the recommendations of experts.

The purpose of rotation

The purpose of regular tyre rotation is to produce a more even wear for all tyres on a vehicle.

Before rotating your tires, check your vehicle owner's manual for rotation recommendations. If no rotation period is specified, tires should be rotated approximately every 10,000 kms, or sooner -- especially if signs of irregular or uneven tyre wear are evident. Have the vehicle checked by a qualified technician to determine the cause of the wear problem. The first tyre rotation is the most important.

Irregular tyre wear

Sometimes irregular tyre wear can be corrected by tyre rotation. Consult your car owner's manual, the tyre manufacturer or your tyre dealer for the appropriate pattern for your vehicle.

If your tyres show evidence of uneven wear, ask your tire dealer to check for and correct any misalignment, imbalance or other mechanical problem involved before rotation. If you don't you may be compounding the problem.

Sometimes front and rear tyres on a vehicle have different inflation pressures. After rotation, adjust individual tyre's air pressure to the amount recommended by the vehicle manufacturer for the tyre's new position.

Do not include a spare tyre designed for "Temporary Use Only" in any rotation pattern.

Caution: Some tyres cannot be rotated in a standard pattern. These tyres include uni-directional tyres and tyres with asymmetric tread designs. Also, some vehicles may have different-sized tyres mounted on the front and rear axles, and these different-sized tyres also have rotation restrictions. Check your owner's manual, or with your tyre dealer or tyre manufacturer, for the proper rotation recommendations in these cases.

Answer : Correct wheel or tyre alignment is essential to good handling capability of your vehicle and plays an important role in tyre life. Misalignment and improper inflation are considered the two principal causes of premature tyre wear. Improper alignment can reduce a tyre's life by more than 70%. The effect is so great, in some extreme cases, that a new set of tyres can be completely worn out in a modest week-end trip.

Signs of incorrect tyre alignment include vibration, shimmy or a tendency for the vehicle to wander, or pull to one side when driven at highway speeds.

If you notice, when you're driving on the highway that the vehicle starts edging to one side or the other rather than maintaining a straight line when you loosen your grip on the steering wheel for just a second, you likely have an alignment defect.

Things which cause misalignment include aggressive cornering, hard braking or bumping a curb.

Alignment involves adjusting the wheels to specifications set by the vehicle manufacturer so they track in a straight line. Mechanics often talk of a front-end alignment since the front wheels are more often the ones that become misaligned.

When a vehicle that is out of alignment is driven the tyres to will wear unevenly, usually on an outer or inner edge (just one side). To avoid damaging your tires, and to make sure the alignment problem doesn't get worse, it's important to correct the situation as soon as possible.

When your mechanic does the alignment, several measurements are checked and adjusted if necessary. These include camber, caster, and toe.

Camber refers to the inward or outward tilt of the wheels. If the tops of the wheels angle in toward the vehicle, this is referred to as negative camber. If the tops angle away from the vehicle, it is a positive camber. When properly adjusted, the camber angle keeps the outside tyres flat and stable on the ground during a turn.

An incorrect camber setting will result in improper handling and tyres will wear out prematurely. If you have too much positive camber, your tyres will wear on the outside. Too much negative camber will wear them on the inside. If there is too much of a difference between the camber settings on the front wheels, the vehicle will tend to pull sharply to one side.

Caster refers to the angle of the vertical axis of the wheel in relation to the steering connection. A high caster angle will produce greater stability at high speeds, but steering may be more difficult at low speed. A lower caster angle results in easier steering, but the vehicle may wander at higher speeds.

Caster is adjusted according to factory specifications on individual vehicles to arrive at the optimum balance -- achieving stability and control at both high and low speeds.

Toe refers to the front end of the wheel just as your own toes are at the front of your feet. Toe-in is a condition in which the front ends of two wheels on the same axle are angled slightly inward so that they are closer together than the heel ends. Toe-out refers to the opposite condition -- the toes of two wheels are angled slightly outward, so that they are farther apart than the heels. Severe toe-in or toe-out causes uneven and excessive wear so that one side of the tread wears out more quickly than the other .

Toe settings affect the handling of a vehicle in turns. Toe-in introduces Understeer going into a curve and may make the vehicle feel like the back end is trying to come around to the front end. Toe-out introduces Oversteer in a curve and makes the vehicle feel like it is "diving" into the turn too sharply.

If the tyres have too much toe-in, the tread will be worn off, starting from the outside edges. If they are toed-out, the wear will start from the inside. This type of wear is called feathering and can be felt by running your fingers across the tread of the tire.

Each vehicle has factory specifications for camber, caster and toe which should be followed precisely. Improper alignment not only causes poor handling and premature tread wear, it also reduces fuel efficiency.

When to Check Alignment

The alignment of your vehicle can be knocked out of adjustment from daily impacts such as potholes and railroad crossings or by more severe accidents. You might want to have your vehicle's alignment checked if:

You know you have hit something with your wheel. You see distinct wear on the shoulders of the tyres. You notice a change in the way your vehicle handles, such as pulling to one side, vibration, wandering.

Question : Tyre Terminology - What does it all mean?