Truck tyres are the tyre sizes used on vehicle such as commercial freight trucks, dump trucks, garbage trucks, box trucks, tow trucks, mobile crane, van and passenger buses. Truck or lorry tyres are sub-categorized into specialties according to the vehicle position as steering, drive axle and trailer. Each type is designed with the reinforcements, material compounds and tread patterns that best optimize the tyre performance
Truck Tyres: History of tyre
Traditionally, metal bands protects rims. However, the use of rubber wheels was not feasible until 1839 when an American investor Charles Goodyear discovered the process of vulcanization, which made rubber stronger, more elastic and less sticky. The first patented tyre was in 1845 by Scottish inventor Robert W. Thomson. Other tyre designs using leather, rubber, and other materials were soon patented.
The first practical pneumatic tyre was made by the Scot, John Boyd Dunlop, in 1887 for his son’s bicycle in an effort to prevent the headaches while riding on rough roads. However, until pneumatic rubber tyres were refined and patented in 1888 by British inventor John Boyd Dunlop, the tyre industry did not flourish. Pneumatic tyres are made of a flexible elastomer material, such as rubber, with reinforcing material, such as fabric and wire. In 1895 the Hartford Rubber Works made the first pneumatic tyre in the United States.
Performance Features Of Truck Tyres
The following are the performance characteristics of the truck tyres; dry traction, tread wear, wet traction, balance, centrifugal growth and rolling resistance.
Dry traction of truck tyres
- It is the measure of the tyre’s ability to deliver traction, or grip, under dry conditions.
- Dry traction increases in proportion to the tread contact area.
- It is a function of the tackiness of the rubber compound.
Tread wear of truck
- The friction between the tyre and the road surface causes the tread rubber to wear away over time.
- There are several types of abnormal tread wear -poor wheel alignment can cause excessive wear of the innermost or outermost ribs of tyre. -over inflation causes excessive wear of the tyre at the middle. -under inflation causes excessive wear of the tyre at the outer ribs. -unbalanced wheels can cause uneven tyre wear, as the rotation may not be perfectly circular.
- It is a measure of the tyre’s ability to deliver traction, or grip, under wet conditions.
- Wet traction is improved by the tread designs ability to channel water out of the tyre foot print and reduce hydroplaning
- When a wheel and tyre is rotated, it will exert a centrifugal force characteristics of its center of gravity.
- This cyclical force is referred to as balance and a non-uniform force is referred to as imbalance.
- A large diameter is developed when a tyre is rotating at higher speed, due to centrifugal forces that force the tread rubber away from the axis of rotation.
- As the tyre diameter grows the tyre width decreases.
- This centrifugal growth can cause rubbing of the tyre against the vehicle at high speeds
Rolling Resistance of truck tyres
- It is the resistance to rolling caused by deformation of the tyre in contact with the road surface.
- As the tyre rolls, tread enters the contact area and is deformed flat to conform to the road way.
- The energy required to make the deformation depends on the inflation pressure, rotating speed, and numerous physical properties of the tyre structure, such as spring, force and stiffness.