A pedal for bicycles comprising: a pedal-pin which extends along a reference axis and has a first axial end structured for being coupled to a pedal crank of a bicycle, a pedal-body that comprises a hub coupled in a freely rotatable manner on said pedal-pin so as to rotate around said reference axis, electronic measurement means, which are firmly coupled to the pedal-pin and configured to provide electrical measurement signals indicative of the deformation of the pedal-pin caused by the force exerted by the cyclist on the pedal-pin during the pedalling, a mechanical clamping member which is structured so as to axially clamp said hub of the pedal-body to said pedal-pin, characterised in that: said pedal-pin has two annular shoulders coaxial with the reference axis; on said pedal-pin an annular seat is obtained, coaxial with said axis, said annular seat has two inner side walls each forming a relative said annular shoulder of said pedal-pin, said mechanical clamping member comprises: a first clamping element which is arranged on said pedal-pin to rotate around the reference axis and is positioned in abutment against at least on of said shoulder in order to be axially clamped along said axis, said first clamping element is arranged in said annular seat such as to slide in the same, thus being able to freely rotate on the pedal-pin around the reference axis and remains axially trapped in the annular seat in abutment against at least one of said annular shoulders. and a second clamping element that firmly couples said hub to said first clamping element so that said hub is axially clamped onto the pedal-pin. a pedal-pin which extends along a reference axis and has a first axial end structured for being coupled to a pedal crank of a bicycle, a pedal-body that comprises a hub coupled in a freely rotatable manner on said pedal-pin so as to rotate around said reference axis, electronic measurement means, which are firmly coupled to the pedal-pin and configured to provide electrical measurement signals indicative of the deformation of the pedal-pin caused by the force exerted by the cyclist on the pedal-pin during the pedalling, a mechanical clamping member which is structured so as to axially clamp said hub of the pedal-body to said pedal-pin, said pedal-pin has two annular shoulders coaxial with the reference axis; on said pedal-pin an annular seat is obtained, coaxial with said axis, said annular seat has two inner side walls each forming a relative said annular shoulder of said pedal-pin, said mechanical clamping member comprises: a first clamping element which is arranged on said pedal-pin to rotate around the reference axis and is positioned in abutment against at least on of said shoulder in order to be axially clamped along said axis, said first clamping element is arranged in said annular seat such as to slide in the same, thus being able to freely rotate on the pedal-pin around the reference axis and remains axially trapped in the annular seat in abutment against at least one of said annular shoulders. and a second clamping element that firmly couples said hub to said first clamping element so that said hub is axially clamped onto the pedal-pin. a first clamping element which is arranged on said pedal-pin to rotate around the reference axis and is positioned in abutment against at least on of said shoulder in order to be axially clamped along said axis, said first clamping element is arranged in said annular seat such as to slide in the same, thus being able to freely rotate on the pedal-pin around the reference axis and remains axially trapped in the annular seat in abutment against at least one of said annular shoulders. and a second clamping element that firmly couples said hub to said first clamping element so that said hub is axially clamped onto the pedal-pin.