The invention relates to a tensioning ring (1) having a tensioning section (3), the tensioning section (3) comprising a wedge element (6), a guide member (7a) and a tensioning screw (5), wherein a width of the tensioning section (3) and thus a circumference of the tensioning ring (1) can be changed by tightening the tensioning screw (5), for which purpose the wedge element (6) is guided at the guide member (7a) and is movable in this guide along a movement way (20a) at the guide member (7a) by tightening the tensioning screw (5), the movement way (20a) having a portion in a width direction (4) determining the width of the tensioning section (3), wherein the wedge element (6) and the guide member (7a) engage in one another with an undercut in such a way that they are held together in a form-locking manner with respect to the width direction (4).