Frequently Asked Questions
Proper inflation is the single most important part of tyre care, tyre pressure is not determined by the type of tyre or its size but upon your vehicle’s load and driving application i.e. speed.
To find out what your car’s tyre pressure should be, consult the manufacturer’s tyre placard usually found inside the driver’s door sill, glove box, fuel filler cap or under the bonnet. The placard also displays the manufacturers recommended tyre sizes.
Tyre pressures should be checked when the tyre is ‘cold’, as pressure increases as the tyre becomes ‘hot’. Take the “cold” reading and check them against the recommended tyre pressures from your placard. Heavy loads or towing puts an extra strain on your tyres.
So if your vehicle is fully loaded with passengers and luggage, the general rule is to add 28kpa (4PSI or 4lbs).
At high speed, (defined as driving at 120km/h for over one hour), your tyres will wear out twice as fast as when you drive at 70-80 km/h.
If your tyres are under-inflated by twenty per cent tyre life can be reduced by thirty per cent. The rule here is to add 28Kpa (4PSI) from your Minimum Compliance Plate Pressure.
Don’t inflate your tyres above 40 psi or 280 kPa. When the tyres get hot from driving, the pressure will increase even more.
Always check your spare tyre.
It is crucial to know when it is okay to have a tyre repaired and when a tyre should be replaced.
If a tyre loses its air pressure, it must be removed from the wheel for a complete internal inspection to be sure it is not damaged.
Tyres that are run even a short distance while flat are often damaged beyond repair. Most punctures, nail holes or cuts up to 6 millimetres can be repaired by trained technicians as long as the damage is confined to the tread.
DO NOT repair tyres with tread punctures larger than 6 millimetres, or any sidewall puncture. Also, never repair tyres which are worn below the wear indicator bars that are located on your tyre, as they wouldn’t conform to New Zealand Land Transport Vehicle Standards.
All tyre repairs should be handled by trained professionals. Your best bet is to keep a good spare tyre in your boot.
Be sure that the spare is inflated to the proper pressure and adheres to New Zealand Land Transport Vehicle Standards.
When any problems with your tyres occur, head to Simpsons Tyres and Autocare for expert service from our trained technicians.
Never try to change your own tyres.
Tyre changing is a job for the people who have the proper equipment and experience.
If you try to do it yourself, you run the risk of serious injury to yourself as well as possible damage to the tyre and rim.
The weight of a vehicle is not evenly distributed to all four car tyres.
Therefore, regular rotation is necessary to maintain even tread wear and get the most out of your tyres. There are several methods of rotation.
For all-season tyres and most vehicles on the road, tyres from the rear axle are moved to the drive axle and crossed to opposite sides of the vehicle.
The tyres from the front axle are moved to the rear, but remain on the same sides. This is known as the ‘modified X’ pattern.
For 4WD vehicles, it is recommended to switch all four tyres, both from side-to-side and in axle position. Check your owner’s manual for the manufacturer’s rotation recommendations. If no rotation period is specified, tyres should be adjusted every 10,000 km’s.
4WD tyres may require rotation as soon as every 4,000 km’s. The first rotation of your tyres is the most important, and be sure to remember to adjust inflation pressures to the vehicle manufacturer’s recommendations after every rotation.
Here at Simpsons Tyres and Autocare can schedule a rotation for your vehicle at any time.
Wheel alignment is the science of precisely measuring and then positioning the wheels on your car to ensure the least amount of wear to your tyres.
When correctly set it will significantly extend the life of your tyres, your car also should handle better, be safer to drive and enjoy greater fuel economy.
Unbalanced tyres cause road vibration, which leads to driver fatigue, premature tyre wear (also known as cupping or dipping) and unnecessary wear to your vehicle’s suspension.
Tyres should be balanced when they are mounted on wheels for the first time or when they are remounted after a repair.
They should be rebalanced at the first sign of a vibration or shimmy, and should be balanced at least once a year.
The cost of keeping your tyres balanced will more than pay for itself in tyre mileage, performance and comfort.
Maintaining the tyre balance on your vehicle is critical to receiving satisfactory service from your tyre investment.
In addition to providing a smooth ride, balancing is a key component in tyre wear.
These tips and advice will help you understand the importance of the balancing process and learn how to keep your tyres balanced throughout their tread life.
It is advisable to avoid mixing different brand tyres on the same axle due to varying construction styles.
It can also be dangerous to mix tyres of different sizes or aspect ratios.
Drop in and see us at Simpsons Tyres and Autocare for expert service from our trained technicians.
Tread wear rates are affected by many factors and there are too many variables involved to allow an accurate answer to this question.
Some will be in the driver’s control but many won’t be.
Factors beyond the driver’s control including road surface, climatic conditions and tyre and vehicle design.
But there are things that the driver can do to influence tyre wear.
“Enthusiastic” driving styles, including high speed operation and cornering, harsh braking and hard acceleration all dramatically reduce tyre life.
Treadwear or life expectancy is determined by many factors.
Driving habits and style of driving, geographical location, type of vehicle, type of tyre, how vehicle is maintained, how tyres are maintained, etc.
As a result, mileage expectancy is impossible to determine.
We suggest that you have your tyres/vehicle inspected by Simpson Tyres and Autocare so that we can find out what is contributing to your rapid or irregular wear pattern.
A bulge or bubble in the sidewall is sometimes the result of damage from coming in contact with a curb, pothole or other object.
If this occurs, we recommend you take your vehicle to Simpson Tyres and Autocare immediately, as this could severely jeopardise the safety of your vehicle.
A tyre that sustains this damaged may not be covered under warranty.
When the shoulder of the tread on one side of a tyre wears faster than the adjacent tread surface, this can result from a variety of conditions, such as front and/or rear misalignment (example, toe or camber), lose or worn suspension components, hard cornering, improper tyre rotation practices, misapplication, high crown roads or non-uniform mounting.