12.5 is the width in millimetres of the tyres cross section.
Radial construction. R stands for radial-ply construction.
15 inches, stands for the diameter of the wheel that the tyre is designed to fit.
- Load Rating108
108 (1000 kg) is the load index i.e. the maximum weight each tyre can carry at full speed.
- Speed RatingS
S (180 kmph) is the speed rating i.e. the maximum speed for the tyre at full load.