SRI TIRE TRADING LTD.
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TIRE KNOWLEDGE NOTES

The principal tire constructions are as follows:
  3-1 3-1) Tire types
 
Radial Tires

This is the type of construction utilizes plies that run radially from bead to bead under the tread. This construction requires belts to stabilize the tread and define the tire diameter. This construction gives greater strength to the tread area thus improving tread life, while the casing remains flexible during cornering.

Bias or Cross Ply (Diagonal) Tire

These types of tires may have 2, 4 or more casing plies, which cross at an angle of approximate 35 degrees to the center line of the tread, giving strength to both the sidewalls and tread. Alternating plies are angled in opposite directions.		  
 
  3-2 3-2) Dimensions
 
Measurements should be taken on an unloaded tire mounted on its measuring rim at the specified inflation pressure, and allowed to stand for a maximum of 24 hoursat normal room temperature before readjustment of the pressure back to its original level.

‡@Rim diameter
Diameter of the rim from bead seat to bead seat.

‡AOverall diameter
Diameter of an inflated tire at the outermost surface of the tread.

  

‡BOverall width
The linear distance between the outside of sidewalls of an inflated tire including elevations due to labeling (marking) decorations, or protective bands or ribs.

‡CRim width
Distance between the inside of the rim flanges.

‡DSection height
Distance from the bead seat to outer tread surface of an inflated tire.

‡ELoaded section height
Distance from the bead seat to outer tread surface of an inflated tire under a specified load.

‡FFree radius
Distance from the axle center to contact surface of an unloaded and inflated tire.

‡GLoaded radius
Distance from the axle center to the outer tread surface of an inflated tire under the specified load.
 
  3-3 3-3) Tire size designations
 
Several systems of tire size designation are used by the industry.