A bead retaining member includes a body having a concave first concave edge and one or more retaining elements which are distributed over the body along said first concave edge for retaining a first bead of a first size along a first retaining curve having a first retaining radius and for retaining a second bead of a second size along a second retaining curve having a second retaining radius larger than the first retaining radius. The first retaining curve intersects with the second retaining curve at a first intersection point and a second intersection point. The first concave edge is non-circular and is located radially outside of the second retaining curve in a center region of the first concave edge between the first intersection point and the second intersection point and radially outside of the first retaining curve in a first lateral region and a second lateral region.