Tire Sizing Sytem
On the sidewall of a tire, its size, performance, etc. are shown by using numerical symbols.
The LOAD INDEX is a numerical code associated with the maximum load a tire can support. The higher the tire’s load index number, the greater its load carrying capacity.
The SPEED SYMBOL indicates the maximum speed at which the tyre can carry a load corresponding to its Load lndex under service conditions specified by the tire manufacturer.
The ASPECT RATIO of a tire is determined by dividing a tire’s section height by its section width when the tire is: Inflated to maximum air pressure, Mounted on the approved measuring rim, and under no load.High performance tires usually have a lower aspect ratio than other tires. This is because tires with a lower aspect ratio provide better lateral stability. When a car goes around a turn lateral forces are generated and the tire must resist these forces. Tires with a lower profile have shorter, stiffer sidewalls so they resist cornering forces better.