Tyre Tips

VEHICLE ALIGNMENT:

Vehicle alignment is one of the most important factors in not only vehicle care, but tyre care. Improper alignment on either the front or rear wheels can result in unusual tread wear, damage to your suspension, and unusual handling for the car. Wheel alignments should be performed every time you install a new set of tyres, and any time you experience an impact such as a large pot hole, curb, or other obstacle. For maintenance purposes, alignment should be checked every 10,000 km .

There are several alignment types, including both two and four wheel alignment. Four wheel alignment is always recommended, but some vehicles are not able to have the rear alignment adjusted. Consult with an alignment specialist you trust to find out what's best for your car.

Warning signs that you might need an alignment are your car pulling or drifting to one side or another, and irregular tyre wear.

ALIGNMENT Camber View

Variations in negative camber can be used to improve the handling of a vehicle. A setting of 1/2° negative on both sides will improve cornering without affecting tyre life greatly.

This negative setting compensates for the slight positive camber change of the outside tyre due to vehicle roll, thereby allowing a flatter tire contact patch during cornering. Excessive negative camber wears the inside of the tyre and similar to positive camber, it can cause wear and stress on suspension parts.

Slight positive camber results in a dynamic loading that allows the tire to run relatively flat against the road surface. Positive camber also directs the weight and shock load of the vehicle on the larger inner wheel bearing and inboard portion of the axle rather than the outboard bearing.

Positive camber in moderation results in longer bearing life, less likely sudden load failure, and as a side benefit, easier steering. Excessive positive camber wears the outside of the tyre and can cause wear to suspension parts such as wheel bearings and axles.

ALIGNMENT Caster View

Positive caster gives a vehicle directional stability because the tire is being pulled along by the load which is projected in front of the center of the tyre contact area.

This causes a vehicle with positive caster (point of load ahead of the point of contact) to be harder to steer away from the straight ahead position. With Positive caster, road surface variations have a minimal effect on the tyre, the tyre will continue to go straight.

When a tyre has a Negative caster condition, where the projected steering axis point of load is behind the tyre point of contact, a vehicle will have a tendency to be easier to steer but will lack directional stability. A vehicle with negative caster is affected by any road surface variation such as small road irregularities or bumps.

With the point of load pushing the tire along (negative caster), any bumps or road irregularities which are encountered have a tendency to immediately affect directional stability and vehicle handling.

ALIGNMENT Toe View

Excessive toe increases tyre scuffing and results in tyre wear and drag on the vehicle. Excessive toe-in, or positive toe, increases scuffing on the outside of the tyre.

Excessive toe-out, or negative toe, increases scuffing on the inside of the tyre, and in some cases can cause a darting or wandering problem. Bias or bias-belted tyres will commonly show a featheredge or saw-tooth toe wear pattern across the entire tyre tread area. Any tyre wear pattern caused by a toe condition can be further affected by an excess camber condition and may result in irregular wear patterns.

TYRE ROTATION

Because each tyre on your car typically supports a different amount of weight, and your driving patterns will typically wear out one tyre faster than the others, it's important to rotate your tyres every 10000 kms. Rotation patterns differ depending on what kind of vehicle you drive. The best place to check is in your vehicle's owners manual.

If you can not find what you are looking for, below are some diagrams showing you the most common patterns. Of course, if your vehicle has different sizes of tyres from front to back, or if your tyres are directional, these may not work. Consult a professional if you are still not sure.

PUNCTURE REPAIRS

A puncture to any area of a tyre's tread will affect performance and safety, and therefore must be immediately attended to through either replacement of the tyre (spare or new tyre) or a patch/plug. Any patch that is applied to a tyre must be applied to the inner part of the tyre. The reason for this is that the rubber on each side is very different (inside is made of halobutyl rubber meant for holding air, while the outside is a harder durable rubber primarily designed for traction). A good tyre repair can only be made if the tyre is removed from the rim (wheel) and inspected carefully for any hidden damage. Only straight through holes, 4.5mm or smaller diameter may be repaired, when no secondary damage has occurred.

AIR PRESSURE

Are your tyres set at the optimum inflation? Chances are they are anywhere from 8psi to 18psi less than recommended. The most common way of damaging tyre is improper inflation. Low air pressure causes tyres to experience irregular treadwear as well as poor vehicle handling and traction.

Under inflated tyres can build up excessive heat and blow out without warning. Keeping your tyres set at the manufacturer's recommended pressure is one of the easiest ways of saving petrol, increasing tyre treadlife, and ensuring safety. If your tyres are inflated to 26psi, and you increase the air pressure to 36psi, your fuel mileage will increase (an average increase of 10%!) Always check your air pressure and make adjustments when the tyress are cold (tyres have not been driven for 2 hours). Air pressure should be checkedonce evry couple of weeks at the very least. This is important because as outside temperatures change, so does tyre air pressure. A 10 degree drop in temperature can reduce tyre pressure by 1psi. That means if you set your pressures in the July and don't check them again until December, you could have lost several psi, decreasing fuel mileage and causing pre-mature tyre wear.

Also remember to check your spare tyre for loss of air. If you are unsure how to use an air pressure gauge and hose, your local tyre shop should be able to show you how. Always use a good quality tyre pressure gauge that is not on a hose.

The tyre gauges built into the air hoses at your local garage have generally not been maintained and can not be trusted to be accurate. *Note, air pressures can be “tuned”, however you should NEVER exceed the maximum pressure branded on the tyre’s sidewall, and NEVER set pressures lower than recommended in the vehicle’s owners manual. Also, if you have altered your tyre size from original, then the minimum pressure may need to be adjusted. Consult a rim/tyre professional for correct pressures.

Run Flat Tyres

Run Flat tyres have been developed based on the specifications of the vehicles on which they are mounted. ... Run Flat tyres must be mounted in conjunction with a functional tyre Pressure Monitoring System.

With run flat tyres,* if your tyre gets punctured, there’s no sudden deflation – meaning you can continue driving safely. They provide greater control of your car in emergency conditions and allow you to continue driving safely even during a rapid loss of inflation pressure. With Run Flat, you will retain mobility in the event of a puncture. So, if your tyre is punctured, even in pouring rain, the Pirelli Self-Supporting Run Flat means you don't have to bother with the spare. Instead, you can continue driving for a limited period.

To ensure maximum safety during an emergency situation, the Run Flat tyre must maintain certain speed and distance parameters (80km/h for 80km). Due to these restrictions, it's imperative that motorists be notified when a loss in tyre pressure occurs, and therefore the vehicle must be equipped with a TPMS (Tyre Pressure Monitoring System) to detect and signal tyre pressure changes.

Most manufacturers advise against repairing run flat tyres. If the deflated tyre has been driven on, it could have compromised its strength, and it is impossible for a fitter to know if the tyre was driven on for longer/faster than recommended after a puncture.