The roller incorporates an elastomer rim (1) which has a bore (30) and shouldered recesses (26) at its sides. Discs (27) are mounted in the recesses so that the rim is supported on the edges of the discs. The discs are secured in position with screws (20) which pass through the part of the rim which lies between the discs. A ball bearing is also clamped between the discs (27). The roller, with bearing, is mounted on a shaft which is built-up from a bush (3) and washers (8) which are held together by screws (15,25).
