There is a transfer of energy going on at that moment. But the product of the energy, HEAT, is not occuring at the brakes, its occuring within the "engine" which provides power to the "grip" Mechanical stress is going on at the grip which at the moment is ONE part. It will also be occuring in every link between the "engine" and the "grip". There will be minute heat associated with this stress undetectable until one part becomes two under load (friction).