The grip and tread rigidity doesn’t come from big tread blocks. The ADVAN dB has nice, small petite ones. It comes from a fancy rubber compound that’s unpronounceable even with elocution lessons. At a micro level the rubber doesn’t distort like a normal tyre and it doesn’t produce as much heat (or energy loss according to the scientists). This results in a tyre that's 9.4%* lighter and has a lower rolling resistance. Both of which improve fuel economy.
The load rating (represented by the numerical value) is related to the maximum weight that tyre can carry. So in this case 105 would refer to a load capacity of 925kg, with most passenger vehicle load indexes range from 62 to 126.
In all instances the tyres load index must meet or exceed the value displayed on the vehicles placard.
The speed category symbol, for example 'S', indicates the maximum speed at which the tyre can carry a load corresponding to its load index. So in this case, 'S' would refer to a maximum speed of 180km/hour.
See the chart below for a full list of speed symbols and their applicable values.