195 = 195 millimeters.This is the nominal section width of the tyres .

55 = 55%. Described as the aspect ratio. This mark represents the height of the tyre sidewall as the precentage of the nominal section width. 

r =Radial construction

16 = 16 inches. This is the diameter of the tyre's inner rim in inches.

87 =Load index rating (The tyre load capacity).

v =Speed symbol indicates the maximum speed for the tyre at the full load (in this case up to 189km/h).