The stability of the motorcycle is maintained by the spinning wheels, to which the spinning rear wheel contributes approximately 80% and the front wheel 20%. However, the front wheel supplies anything from 80-100% of the braking performance.
Our Queensland motorbike training course explains how, in most motorcycles, the braking performance exceeds the tyres ability to provide traction, which can result in a skid. Skids are undesirable as they dramatically affect the stability and therefore predictability of the motorcycle.
So you can get the idea that it is a good idea to keep your wheels spinning, particularly the back wheel, and avoid skids. It is difficult to precisely gauge the amount of traction afforded by various road surfaces, obviously dirty, wet and rough road surfaces would provide differing amounts of traction.
The idea is to apply both brakes in a way that eliminates the chance of a skid of either wheel.
So, practice and experience will provide clues as to the performance of your tires when under braking pressure in various conditions. At the start of a braking action it is a tip to use 80% front and 20% rear under normal conditions, however importantly remember to first let off the rear brake as speed washes off and too then ease off the front brake as you come to a stop. Remember to try and avoid sudden actions and to use 50% front and 50% rear when riding your motorcycle under adverse conditions.