A system for determining a torque applied between two rotating members about an axis of rotation (R), said system comprising: - a test body having an internal ring secured in rotation to means for coupling said test body to a first one amongst the members , and an external ring extending around the internal ring while having means for coupling said test body to the second one amongst the members , said rings being concentrically linked around the axis (R) by a deformable structure which is arranged to transmit the torque between the members while enabling an angular displacement between said rings according to the torque applied between said members; - two encoders, respectively an internal one secured in rotation to the internal ring and an external one secured in rotation to the external ring , each of said encoders carrying a track capable of emitting a periodic signal representative of the rotational displacement of the corresponding ring ; - a device for determining the torque comprising a support carrying an internal sensor and an external sensor , each of the sensors comprising a pattern of sensitive elements arranged at a reading distance (E) from the internal or external track to output a signal representative of the angular position of the corresponding encoder , said device comprising means for comparing the signals outputted by each of the sensors to determine an angular offset between the rings which depends on the applied torque; - a casing in which the test body, the encoders and the determination device are housed, said casing having an outer wall ; said system being characterised in that the outer wall has a cavity forming a compartment in which a subplate is fastened, said subplate being associated with the support by means of a setting screw which is arranged so that the rotation of said screw induces a translation of said support relative to the test body to enable setting of the reading distance (E) of the tracks by the respective sensors . - a test body having an internal ring secured in rotation to means for coupling said test body to a first one amongst the members , and an external ring extending around the internal ring while having means for coupling said test body to the second one amongst the members , said rings being concentrically linked around the axis (R) by a deformable structure which is arranged to transmit the torque between the members while enabling an angular displacement between said rings according to the torque applied between said members; - two encoders, respectively an internal one secured in rotation to the internal ring and an external one secured in rotation to the external ring , each of said encoders carrying a track capable of emitting a periodic signal representative of the rotational displacement of the corresponding ring ; - a device for determining the torque comprising a support carrying an internal sensor and an external sensor , each of the sensors comprising a pattern of sensitive elements arranged at a reading distance (E) from the internal or external track to output a signal representative of the angular position of the corresponding encoder , said device comprising means for comparing the signals outputted by each of the sensors to determine an angular offset between the rings which depends on the applied torque; - a casing in which the test body, the encoders and the determination device are housed, said casing having an outer wall ; <EOS>