Method in reeling up and a reel-up

Before a reel change a new core ( 5 ) is brought to a change station. When the old reel (R) is full, the web is changed to travel to the new core periphery and primary reeling beings. The web forms a reel through a reeling nip (N 1 ) between the loop of an endless supporting member ( 1 ) and the core. A change is made to secondary reeling, where a portion of the supporting member ( 1 ) brings the web to the reel, to move over to the reel in a nip (N) between said portion and the reel outer periphery. The core ( 5 ) is transferred so the nip (N) moves forward. A first guide roll ( 2 ) is transferred towards the core periphery so the distance of the nip (N 1 ) located between the core ( 5 ) and the loop of the supporting member ( 1 ) from the first guide roll ( 2 ) changes in the primary reeling.