Abstract: Rubber compositions filled with an unusually high content of solid magnetizable particles such as iron oxide or strontium ferrite but having great resistance to crack initiation and crack growth. This allows generation of strongly magnetized areas in rubber articles built with a rubber composition according this invention. This gives—also in those applications where a large distance between a row of magnetized areas and a sensor is necessary due to deformation—well-reproducible and well-recognizable signals despite existence of disturbing magnetic fields. The magnetizable particles are bonded to a rubber matrix by a bonding agent, namely an organo-functional silane.