brake disk 2 with a locally reduced section modulus w 1 to wn the position of the reduced section modulus w 1 to wn in the brake or friction rings 3 4 occurs as a result of the selection of the number u201c x u201d of the locally weakened section moduli w 1 to wn for example x 4 as in the following the locally reduced section moduli w 1 to wn are formed by slots 10 in the first friction ring 3 the second friction ring 4 or both of these friction rings according to one embodiment the slots 10 separate the brake ring 3 and or 4 so that at u201c x 4 u201d four partial segments s 1 to s 4 are obtained fig6 to 10 illustrate several embodiments having various arrangements of the slots 10 locally reduced section moduli u201c w1 to wn u201d corresponding to the natural oscillations for u201c es u201d and the resulting modes u201c k u201d are obtained such is illustrated for example in fig9 by way of five segments s 1 to s 5 according to fig6 the slots 10 are arranged in the inner friction ring r 1 according to fig7 the slots are arranged so as to alternate in the outer and inner friction rings r 2 r 1 and according to fig8 the slots are arranged in both friction rings r 1 and r 2 arrangements of the slots 10 similar to those of fig6 to 8.