APPARATUS AND METHOD FOR ESTIMATING A GRIP FACTOR OF A WHEEL OF A ROAD VEHICLE AND RELATIVE ROAD VEHICLE

Apparatus for estimating a grip factor of at least one wheel comprising: a control unit configured to process a current slip angle of said wheel; a storage unit, within which, in a consultation table, a plurality of grip curves correlating a plurality of values of a steering parameter comprising the rack force with a plurality of values of the slip angle are recorded; along a same curve, the value of the grip factor remains unchanged; wherein the control unit is configured to cyclically estimate at least one raw value of the grip factor of said at least one wheel based on the position of a current condition within the consultation table, as a function of the current slip angle and of the current rack force.