TIRE ACTING FORCE MEASURING METHOD, AND TIRE ACTING FORCE MEASURING DEVICE

There is provided an apparatus for measuring forces acted upon a tire in which a radial force and a peripheral force acting to the tire, which are required for the high precision measurement of a friction coefficient on a road surface, are simply measured in a high precision by detecting a magnetic field formed by a magnet fixed to a tread portion of the tire by a magnetic sensor fixed to a rim and measuring the forces acting to the tire from a variant pattern of a magnetic flux density detected un the rotation of the tire and without influencing upon the balance of the tire, which contributes to the high precision measurement of the friction coefficient on the road surface.