How To Read A Tyre

Tyre Designations
DIMENSIONS	EXPLANATION
300-4	Tyre width 300 / Rim Diameter 4"
10x3	Former designation in inches: Tyre Width 3” / Tyre diameter 10” ( =3” x 2 + 4”)
260x85	Designation in millimetres: Tyre diameter 260mm / Tyre width 85mm The former designation in inches converted to mm: 10” x 25.4 = approx. 260mm 3” x 25.4 = approx. 85mm
85/100-4	This is how the designation would be, had it been a passenger car tyre. Tyre width 85mm / Profile 100% / Rim diameter 4”.
10x3.00-4	American designation, mainly used for low proflie and turf tyres: Tyre Diameter 10” / Tyre Width 3” / Rim diameter 4”

LOAD AND SPEED RATINGS

On the sidewall of a tyre you can find the load index and Speed Symbol following the key sidewall size markings.

The Load Index is a numerical code associated with the maximum load a tyre can carry
The Speed Symbol indicates the speed at which the tyre can carry a load corresponding to its load index.