Other Tire Construction
Tires can be classified according to the arrangement of the cord layer, into the radial tire and bias tire (cross-ply tire). But most of the tires used at present are radial tires thanks to their proper advantages. Tires can also be classified according to the method of retaining inflation pressure, into the tubeless tires and tube-type tires, but most vehicles currently adopt tubeless method.
Radial Tire and Bias Tire
- Structure of the radial tire
- The cords forming the carcass are arranged perpendicularly to the centre line of the tread or in a radial direction from the centre of the circle.
- Structure of the bias tire (cross-ply tire)
- The cords forming the carcass are intersected at a diagonal (biased) angle of about 40° with respect to the tread centre line.
- (A) Radial tire
- (B) Bias tire
- (C) Side view
- (D) Front view
- Arrangement of carcass cords
Advantages of the radial tire
- 1. High-speed durability.
- 2. Low heat generation.
- 3. Low rolling resistance, contributing to fuel saving.
- 4. Better wear resistance.
- 5. Excellent cornering ability and stability.
- 6. Less slipping and high traction force.
Radial Tire and Bias Tire
The tubeless tire does not use a tube. Instead, it maintains inflation pressure in the tire by the attachment of a special rubber liner called the “inner liner,” that features low air permeability on the internal surface of the tire. While the valve of a tube-type tire is attached to the tube that of the tubeless tire is a special valve attached directly to the rim.
- (A) Cross sections of a tubeless tire and a tube type tire
- (B) Tubeless tire
- (C) Tube-type tire
- (D) Advantages of the tubeless tire
- Innner liner
- Tubeless valve
- Tube valve
- Side/Lock ring
- 1. The absence of a tube has eliminated the problems that were formerly related to the tube.
- 2. Air does not leak suddenly even if the tire is pierced by a nail or other sharp object, thereby contributing to the prevention of accidents resulting from tire damage.
- 3. Air is in direct contact with the rim, thereby improving the heat dissipation.
- 4. Helps to decrease the tire weight, reduces its cost and enables easier tire maintenance.
- 1. Special care is required when assembling the rim because damage to the bead tends to promote air leaks.
- 2. Check the rim and valve for damage and deformation periodically, as these may be a cause of air leaks.
- 3. Although a tubeless tire is not susceptible to sudden and rapid air leaks, a driver tends not to notice any drop in the tire’s internal air pressure. This makes it necessary to check the tire, wheel and inflation pressure periodically.
The runflat tire is designed for use as a standard tire that does not need to be supported by a spare tire. The sidewalls are reinforced with rubber so that, even in the case of a puncture, the tire can continue running for a while.
- (A) Cross-section of runflat type tire
- (B) Ordinary tire
- (C) Self supporting runflat tire
- (D) Cross-section of a tire at zero pressure (Image)
- Wfeel rim
- Reinforced sidewall
- Self supporting reinforcement
* With run flat tires it is not easy to identify any decrease in pressure, even if this is due to a puncture. For this reason, in the case of runflat tires installed it is necessary to mount an inflation pressure alarm unit in order to detect any air leakage.