195 indicates the section width of a tyre in millimetres.
65 is a tyre’s aspect ratio which is its height from the base of the tread to the rim.
This number represents a percentage of the tyre’s tread width.
R means that the tyre has radial ply construction, meaning the way in which it has been constructed.
15 indicates the diameter of the wheel rim.
Load & Speed
91 V is a reference that indicates the maximum load capacity and speed at which a tyre can be safely operated, subject to the tyre being in sound condition, correctly fitted and with the recommended inflation pressure.
See load index table here.