These openings have the drawback of limiting the maximum permissible size of the collar's radius. Indeed, the collar is strongly acted upon by centrifugal force; if openings are made in it, in order to obtain the desired passage section, it is often necessary to increase the distance between two discs and therefore the length of the brace. This increase in the length of the brace, added to the effect of the shape coefficient due to the holes, raises the level of local stresses, in particular bending stresses, thus the necessity of reducing the diameter of the brace collars.