Tyre Knowledge

4 Major Functions

A tire can provide a vehicle with 4 major functions.

Construction: Radial Tire and Bias Ply Tire


Radial ply casing cords are placed across tire from bead to bead. In addition radial tires have breaker plies running circumferentially around the tire under the tread.

Bias ply tires have even numbers of plies with each ply in adjacent directions from bead to bead. The tires may additionally have narrower plies under the tread.

The construction can be determined by size designation. Radial tire has "R" while Bias ply tire has hyphen.

Radial ply tire has the advantages in Road holding, Cornering stability, High speed stability, Noise, Rolling resistance and Tire Life. Bias ply tire has only advantage in riding comfort.

Tubeless and Tube Tyre

In tubeless tire innerliner is attached to the inside of the casing in stead of tube and flap (to protect tube). Therefore in tubeless tire there is less number of parts to manage as well as less heat build up and safer. because of less chance of sudden air loss due to rapture.

Tread Pattern

New device for the features for TBR
Decoupling groove : Groove to fight irregular wear at shoulder rib.
Wandering defense groove : Groove to fight rut wandering wear at 2nd rib.
Edge sipe : Micro sipe at shoulder groove
Stone ejector : Elevation at bottom in grooves in tread center  
Open/Solid shoulder : Open shoulder block for more wet grip and solid for stability and 
  resistance to irregular 
Land/sea ratio : Ratio of solid area against void in tread pattern
Pitch length : Circumferential length of tread pattern
Pitch variation : Varying pitch length into 3 or 5 different variation 

Dynamic Characteristics

Then a tire is rotated, behavior of the tire without rotating is called "Dynamic Characteristics".

<Rolling Radius>
When a tire is loaded and rotated, the distance made by one rotation divided by is called "Rolling Radius", which stands for the actual radius at certain speed.

Revolution per mile is calculated by;
=1609344/(2n*Rolling Radius)
=1609344/Distance of a rotation
(in mm)

<Rolling Resistance>
When a vehicle runs, the engine's power will be consumed by the following resistance.
*Aerodynamic Resistance
*Tire Rolling Resistance
*Power train & Mechanical Resistance
In addition, acceleration and uphill resist-ance will also consume power, if applicable.
Rolling resistance consists mostly of energy loss due to flexing movement while rotating.
Rolling resistance is affected by greatly by vehicle speed as well as inflation pressure.
Therefore speed reduction and proper inflation pressure is quite effective way to save fuel trucking company.


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