Want to get the most from your tires?

It is critical for fleet managers to take a close look at their costs and determine where they can squeeze the most out of their operation and stay competitive in these challenging economic times.

There are still some fleets and individuals within the transportation industry that don’t realize that tires can comprise a significant portion of their operating cost - often the third-highest cost after labor and fuel.

Depending upon the application and environment that tires operate in, tires can experience “punishment” that will shorten the life expectancy of the tires, as well as the performance. That is why it is so important to utilize the tire that has been optimized for your specific application and environment.

For example, an urban tire operating in the city experiences different challenges than one utilized in regional or long haul applications. In urban applications, the tire sidewalls take the brunt of curb damage, while treads are subject to scrubbing and punctures from nails and other debris.

Significant temperature changes can result in unanticipated pressure changes during operation. Extremely high temperatures caused by braking and overloading are also major concerns.

In long haul, regional operations, on-/off-road, etc., the tires will face different challenges that will affect the life and performance of the tires.

Tires are application-specific and designed to deliver different performance criteria in different applications and under different conditions. The fleet must understand their application, road conditions and operating environment.

Understand Tire Technology

That’s why it’s important that fleets understand the technology behind tires and how to choose the right tires for their application so that the tires will provide the best overall value for the fleet and the bottom line.

While the vast majority of the commercial vehicle market has been running radial tires for several decades now, radial tire technology, which was first developed for commercial vehicles in 1953, provides the foundational basis for additional advancements, allowing tires to better operate in difficult environments. Radial tires are fundamentally different than their bias-ply predecessors.

The radial tire is constructed in two parts. First, a single layer of rubber-coated steel cables arches from one bead to the other to form the tire casing. Second, numerous rubber-coated steel belts are placed in the crown, under the tread, to form a strong stabilizing unit.

To increase a radial tire’s strength, larger diameter steel cables can be used. These steel cables help reduce punctures, tears and flats. They also help distribute heat, resulting in a cooler running tire, improving fuel economy.

The combination of stabilizing steel belts and the single-layer radial casing allows the tread and sidewall to act independently. The sidewall flexes easily under the weight of the vehicle and its cargo, while the tread helps provide even contact with the ground.

Greater vertical deflection is achieved with radial tires.

The stabilizing steel belts and radial construction help minimize tread distortion. As the sidewalls deflect, the belts hold the tread firmly on the ground, minimizing tread scrub and greatly increasing tread life.

The independent action of the tread and sidewalls keeps the tread flat on the road when negotiating curves and encountering side forces. This allows the tire to hold to its path.

By keeping the two sections free from each other, the tire’s overall performance is enhanced, but the separation also allows tire designers to specifically enhance or customize the tread or sidewall area with specific rubber compounds, designs or other technologies to improve the performance of that portion of the tire.

Because of this foundational aspect of radial tire technology, tire designers can make additions to the structural support in the sidewall of tires without affecting the crown area. This allows for stronger, more damage-resistant, sidewalls.

Special rubber compounds are often used in the sidewall area as well, to further guard against cuts and abrasions from the debris or curbing typically associated with the urban application.

Other applications of tire technology can be found in the tread area, which provides several opportunities to increase the efficiency and effectiveness of a tire. By way of example, in the mixing of the tread rubber, Michelin deploys its Advanced Technology compounding, which uses layers of rubber to deal with the many demands made on the tread area of the tire.

The bottom layer of rubber is more heat-resistant to protect the casing from overheating and providing a greater opportunity that the casing could be retreaded. The top layers of tread rubber are designed with compounds that are capable of withstanding the higher degree of scrubbing that comes with frequent starts, stops and turns.

These characteristics are uncompromised by the need for tread rubber to be fuel-efficient, in addition to providing greater fuel savings. Furthermore, the tread design can provide significant improvements in wear rate and avoiding irregular wear, as well as fuel efficient designs, which tend to be more rib-like, as opposed to block-type tread designs.

Doug Jones is the customer engineering support manager for Michelin Americas Truck Tires. He has been employed with Michelin for more than 34 years in various technical, engineering and management positions. Dedicated to the improvement of sustainable mobility, Michelin designs, manufactures and sells tires for every type of vehicle, including airplanes, automobiles, bicycles, earthmovers, farm equipment, heavy duty trucks and motorcycles. www.michelintruck.com.