A tool for mounting and removing tires onto and from respective wheel rims comprises a profiled body mounted on a cylindrical shank provided at the end of a tool holder bar associated with a tire removal machine. The body has two active portions: the blade and the head. The blade and the head extend from two parts comprising coaxial hubs, both of which are mounted on the cylindrical shank of the tool holder bar and removably coupled together such that their mutual orientations can be adjusted. At least one of the hubs is provided with means for torsionally locking the hub to the shank.