- Advanced Technology compounding allows the company “to very finely tune the volume and profile of two or more unique rubber mixes to deliver a seamless single semi-finished component in the tire making process,” Baldwin says. This technology is used in not only the tread area but also the sidewall rubber.
In terms of tread rubber, the compounding “enables the most robust, highest-performing compounds to be used for the tire/road interface, while using cooler running compounds to form a precisely contoured lower layer to protect the casing from excess heat in some cases - helping retreadability - and further reducing rolling resistance levels in others.
“As for the future of tire technology and tire trends, Baldwin says “fuel efficiency will continue to be a key performance requirement from fleets and owner/operators.”
Hankook Tire’s development engineers are developing new technologies and design strategies to address the need for low rolling resistance tires while retaining other important performance characteristics, says Clinton Covey, truck, bus and RV a development engineer with the company.
“Low rolling resistance tires deliver a significant improvement in fuel mileage, he goes on. “A 3 percent reduction in rolling resistance translates to approximately 1 percent in fuel savings.
“Trucks fitted with low rolling resistance tires may see anywhere from a 1 to 10 percent and upwards savings in fuel, dependent on the tires which were replaced. This means different tires may have rolling resistance performances varying by 30 percent or more.”
Wide-base tires, low rolling resistance compounds and improved manufacturing processes are successfully decreasing the rolling resistance of specific tire makes and models, says Covey.
A tire’s tread rubber accounts for a substantial portion of its mass and typically contributes 35 to 50 percent to rolling resistance, he notes. Therefore, the use of low rolling resistance tread compounds can significantly improve the rolling resistance performance of a tire.
Not only does tread rubber account for a generous portion of a tire’s contribution to fuel economy, it also greatly influences tread wear and traction. “New tread compound development technologies are greatly improving rolling resistance while retaining excellent tread wear, traction and other important performance characteristics.”
Tire manufacturing processes, particularly curing, can be altered to affect certain tire characteristics, including rolling resistance, he explains. The two main manufacturing processes are the assembly of the “green” tire and the curing process.
During green tire assembly, components are wrapped in a particular order around a metal cylinder, forming the composite green tire. This green tire is then inserted into the mold and heated to a high temperature for a certain amount of time, determining the final shape of the tire to include tread pattern and sidewall markings.
“The most significant variables during the curing process are total time in the mold, and the temperature at which the tire is cured at any given time. Varying these parameters appropriately can significantly affect the performance properties of the tire, including improved rolling resistance, he says.
“Advanced finite element analysis modeling aids engineers in making more accurate predictions as to how changes in tire construction will benefit rolling resistance performance. Computer simulation enables the engineer to make changes in cavity shape, component geometry, compounds and other parameters to predict performance through a variety of conditions. Design candidates are compared using this information, leading to a tire optimally designed for rolling resistance and other important performance criteria.
“These tools effectively aid the development process, decreasing development time, saving costs and improving results.”
Trucks having trailer and drive positions fitted with wide-based tires can experience a 1 percent to 10 percent improvement in fuel economy, dependent on the tire models replaced, he says.
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