Load Index And Speed Symbol – Metric Radials

Use of metric tire size marking is the farm tire size trend for the future. Inherent with this metric marking is the use of Load Index and Speed Symbol ratings for the individual tire. The Load Index is a numeric number which represents the load in kilograms or pounds. Any two tires with the same Load Index value have the capacity to carry the same load.
The Speed Symbol is also an alpha-numeric code for the maximum speed a tire is capable of running at the load indicated by the Load Index. These two symbols are used together to give service description for the tire.

Marking – Conventional Size Radials

Construction and performance characteristics of radial agricultural tractor drive tires are considerably different from those of bias ply tires. Therefore, a different approach has been used to effectively recognize these differences. To maximize the benefits inherent in our radial tractor tires in a load/inflation program that will be different but readily understood, Goodyear introduced “Symbol” marked radial drive tires.

All conventional sized radial agricultural tractor drive tires are marked with , or . The maximum load rating for agricultural tractor tires in all sizes is at 18 psi inflation pressure. Maximum load for all agricultural tractor tires is at 24 psi and for all agricultural tractor tires the maximum load is specified at 30 psi.

To clearly recognize the capabilities of the radial tractor tire, a panel cured in each sidewall will show: the symbol marking; the maximum tire load at the appropriate inflation pressure; and a notation on which bias ply rating tire(s) this radial tire will replace.

Here is an example of how the panel will look for a radial agricultural tractor drive tire