TIRES – Useful Info

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TIRES – PRACTICAL ADVICE AND MANUFACTURING

At Autotech Performance, transparency and the quality of the information we provide our clients is important to us. The information and expert advice below are intended to provide you with peace of mind as you drive, no matter the season.

PRACTICAL ADVICE

What should you check regularly to keep your tires in good shape? How can you maximize their lifespan and performance? We recommend that you carry out this inspection at least twice a year.

Tire pressure

The pressure of air-inflated tires varies with the temperature. In winter, air contracts in the tires and pressure decreases. The opposite occurs in summer as air expands in the heat and pressure increases. It’s now possible to inflate your tires with nitrogen, which is less likely to vary with the temperature and therefore helps keep your tire pressure stable, saving you from having to check it frequently.

You should check your tire pressure regularly to keep the pressure at recommended levels and detect any possible slow leaks. Note that a tire can lose up to half its pressure without appearing flat. Keeping the adequate pressure levels is probably the main factor in ensuring your tires’ longevity. In fact, low air pressure is the primary cause of tire failure. With properly inflated tires, your vehicle’s suspension works better, and you get both better handling and better mileage.

Excessive or insufficient pressure can be detected by examining the tire’s wear:

• If the tread is worn outside and inside, the tire is under-inflated.
• If the tread is worn in the middle only, the tire is over-inflated.

Today, most vehicles are equipped with a pressure control system that identifies discrepancies between the tires’ prescribed and actual pressure, monitoring each wheel independently. Only wheels marked “PAX System” can be controlled this way.

Wheel alignment

Wheel alignment is also an important factor in minimizing tire wear. Properly aligned wheels greatly extend the life of the tires. The type of tire wear can indicate if the wheels are out of alignment. Note that all four wheels must be aligned at the same time. Aligning the front wheels only will cause the accelerated wear of the rear tires.

Tire rotation

Radial tires should be rotated regularly from front to back, so they wear out evenly. However, they must remain on the same side of the vehicle.

Spare tire

Most vehicles are now equipped with a space-saving spare tire. It is much lighter and less durable than a regular tire. Its air pressure is usually higher than for a standard tire because of its small size. The pressure in the spare tire should be checked at least once a year to ensure that it will work in an emergency.

Replacing your tires

All tires have wear indicators that show when the tire needs to be replaced. If you see a solid bar across the width of the tire, it’s time to replace it!

HOW ARE TIRES MADE?

Tires are made of fabric, steel and rubber. Mounted on the wheels of a vehicle, they create contact between the vehicle and the surface on which it rides. Every modern car tire supports about 50 times its own weight. The compressed air in the tire supports 90% of the load while the complex structure of the tire (fabric, steel and rubber) supports the remaining 10%.

The wheels are the metal cylinders that connect the tires to the suspension system. Although wheels are often chosen for aesthetic purposes, their function remains critical. The wheel is a major element of the suspension: when it is too small, it interferes with braking; when it is too large, it interferes with the driving and manoeuvrability of the vehicle. Similarly, a wheel that is too wide causes premature wear of the tire and unduly increases the pressure on some elements of the suspension by shifting the suspension’s centre of balance to the outside. An unbalanced suspension increases the vehicle’s instability in corners. It is therefore crucial to choose wheels (and tires) of the right size for your vehicle.

The tread is another critical component of the tire. It must provide a consistent and strong grip to the road to ensure your safety. Each tread pattern (sculpture) is characterized by the geometric shape of the grooves, bars and spaces. The sculpture is one of the main criteria used to select the tire best suited to each type of driving. For instance, when driving on a wet surface, it is best to have a tire whose tread can evacuate the water under the tire’s contact area with the road. Thus, continuous grooves that direct water from the centre to the outside of the tire provide the best grip in such weather conditions. For dry surfaces, tires with a pattern-less tread will provide the best grip and vehicle control. However, since your tires will be subject to various road surfaces and variable weather conditions, you must choose a tread pattern that offers both durability and control under normal driving conditions.

On each side of the tire, the sidewall connects the tread to the heel. The sidewalls have two functions: first, they protect the vehicle by absorbing the irregularities of the road; then, they transfer energy from turns, braking and acceleration to the tire tread. The heels are rubber-coated steel hoops that reinforce the area where the tire’s sidewalls and the rim of the wheel meet. The diameter of the heels determines the size of the tire.

Reinforcing cables are arranged under the tire surface in a crisscross pattern. It is these cables that give the tires their strength. Tires are classified according to the orientation of the reinforcing cables that run through them:

• In a diagonal carcass tire, the cables cross diagonally between the tires’ layers.
• In a belted diagonal carcass tire, there are two or more layers of diagonal cables to which stabilizer belts are fused directly under the tread.
• In a radial tire, the cables run through the tire in a hoop pattern from one heel to the other.

Radial tires’ reinforcing layers are limited to their tread. The lack of diagonal reinforcement in the sidewall makes radial tires more flexible, giving them a better grip and a longer life. It is also what gives them the appearance of being under-inflated.