A method in a reeler and a reeler, wherein a reeling nip (N1) is formed by a reeling core (5) or a growing machine reel (R) and at least one loop of an endless supporting member (1), which is substantially continuous in the axial direction of the reeling core (5). In the method variables proportional to the tension of the endless supporting member (1) are measured and the tension profile of the endless supporting member (1) is determined or the cross-directional linear load profile of the reeling nip (N1) is measured.
