The invention relates to a roller (8) of a support arrangement for a rotary milking platform. The support arrangement comprises a first rail member (4) fixedly connected to the rotary platform (1), a second rail member (5) stationary arranged in a position below the platform (1), and a plurality of rollers arranged in a vertical space between the first rail member (4) and the second rail member (5). The roller (8) is one of said plurality of rollers, and comprises a peripheral contact surface (8c) to be in contact with a contact portion (4d) of the first rail member (4) and a contact portion (5d) of the second rail member (5), and two side flanges (8a, 8b) arranged on opposite sides of the contact surface (8c). Said roller (8) comprises a first unit (8h) and a second unit (8i), a connection mechanism configured to releasably connect the first unit (8h) and the second unit (8i) in a mounted state, wherein the first unit (8h) comprises the first side flange (8a) as well as the entire contact surface (8c) of the, roller (8), and the second unit (8i) comprises the second side flange (8b) of the roller (8). This construction allows for replacement of rollers individually when they wear in an uneven manner.
