Tyre life: the unavoidable VS the avoidable

Tyres are the only link between your vehicle and the ground. The humble tyre does a lot for a hollow piece of rubber: it transfers forces from the vehicle to the road, provides grip at considerable speed and benefits of handling, while maintaining safety and stability.

At the most basic level there are two factors affecting your tyre life – the unavoidable and the avoidable.

Unavoidable factors are typically uncontrollable environmental and task related factors- some of which you may not even consider, such as:

Climatic conditions and air temperature

For every decrease of 1 degree Celsius, tyre pressure drops by approximately 0.19 PSI. Cold weather means less tyre pressure than hot weather. Lower pressure increases the amount of tyre surface in contact with the road, and makes the sidewalls of the tyres more flexible - compromises grip and handling. It also means that the tyre deforms more due to the weight of the vehicle and this causes heat build-up in the rubber, reducing its life.

Nature of work and road surface

The kinds of roads frequented, as well as the types of surfaces covered are significant determinants of tyre life. Vehicles used across on/off road haulage, quarries, country roads or mountainous routes will have a different shelf life to a vehicle used for urban delivery work or long stretches of smooth highways.

The reprieve from these factors are those that are avoidable or at the very least, manageable. Take a look at some of these factors below, and see if you’re doing everything you can to get the most out of your tyres:

Maintenance

• Condition of wheel assembly
• Wheel nuts tightened to the correct torque setting
• Regularly checking for no obvious damage
• Correct twinning (ie. matched duels: tyres of the same circumference, diameter, tread depth)
• Rotation
• Checking for oil, petrol or diesel contamination

Alignment

• Toe in/toe out
• Camber (is it positive or negative?)
• Inter-axle alignment
• Inter-axle alignment

Balance

The purpose of balancing tyres is to reduce wheel vibrations to an acceptable level. There are two types of unbalance:

• Static Unbalance: found by the gravity system without spinning the wheel. Effects include vertical jerking, bouncing and centre wear.
• Dynamic Unbalance: found by spinning the wheel. Effects include wobbling and irregular tyre wear.

Under-inflation

• Excessive wear on the shoulders
• Case deterioration, due to heat
• Excessive casing deflection
• Case deterioration, due to heat

Over-inflation

• Excessive wear in the centre
• Increases likelihood of damage or puncture
• Case deterioration, due to impacts

Driving Habits

• Rapid acceleration
• Heavy breaking and high speed cornering
• Impact damage, eg. kerbs, potholes

Fitting

• Correct tyre size for tyre rim
• Using suitable tyre lubricant, eg. nothing oil based
• No damage to bead area during fitting
• Tyre fitted concentrically on its rim – always check the fitting line to confirm