Tyre wear is inevitable. If manufacturers work to increase mileage performance with each new generation, fleet managers and drivers also have an important role to play to prolong the service life of tyres.
Controlled wear starts with the design
The rate of tyre wear depends on four factors: the intrinsic characteristics of the tyre (type of rubber, tyre pressures, the casing and wearable rubber volume), the mechanical condition of the truck (axle alignment, vehicle alignment), driving style and the road surface.
Tyre manufacturers can tune several parameters to extend tyre life, but the profile design is all about compromise and must not be at the expense of other qualities, such as comfort and grip. Besides the chemistry of tyres, tread wear is directly related to the surface in contact with the ground, since that’s where the entire weight of the truck is spread. The larger the surface area, the lower the pressure… often to the detriment of rolling resistance! The aim is to strike the right balance. Furthermore, even at the scale of a single tyre, manufacturers make sure that the pressure is evenly distributed across the tread, so that the tyre wears evenly. To do this, they focus on the tread pattern, the casing and the belt (steel cables reinforcing the tread), to obtain a “flat” tread that hugs the road surface when driving.
The impact of alignment on tyre wear
Regular checks and maintenance of a truck’s mechanical components is not just about safety, it also concerns the service life of the tractor/trailer assembly, including tyres. Compliance with the manufacturer’s recommended tyre pressures ensures even wear and therefore, tyres last longer. Similarly, it is recommended to rotate tyres and turn tyres on the rim when necessary. When the tread depth reaches 2 to 4 mm, regrooving solutionsare still possible, then retreading to give the tyre a new lease of life.
External parameters can also have an impact on the tyre’s longevity, such as, for example, incorrect settings for the axle alignment(alignment, camber, toe-in...) mechanical playin the steering and suspensions, or abnormal brake heating which may damage the tyre, or even cause it to burst.
Tyre wear also depends on the truck’s own characteristics, starting with engine torque, the efficiency of the braking system and the truck’s weight. Therefore, it is up to the driver to adapt his driving to the vehicle and the load. Frequent demands placed on tyres, such as driving on twisty roads or repeated stopping and starting, tend to increase tyre wear. As well as controlling the laden weight and tyre rating, it is also necessary to reduce sway and balance the load on each axle. Even if the trailer’s total weight is within its load carrying capacity, one of the axles may be carrying more load than the others, which will result in irregular tyre wear.
Like fuel consumption, tyre life is pretty much tied to how the driver drives. When braking or cornering, excessive speed and abrupt handling are detrimental to tyre longevity.
The type of road surface is the last main cause of wear, but the driver cannot always choose his route, and even if it were the case, he would not choose it on the basis of the asphalt friction coefficient! However, when driving on rough ground or in towns, drivers should, whenever possible, avoid obstacles which could damage tyres (pot-holes, pavements, stones…).
By Renaud Lacroix