... belt and moving the materials loaded on the belt. The diameter of the idler could be correctly selected according to the ... travel speed. We produce diameter 60mm, diameter 63.5mm, diameter 76mm, diameter 89mm, diameter 108mm, diameter 114mm, diameter 127mm, diameter 133mm, diameter 140mm, diameter 159mm, diameter 165mm, diameter 178mm,diameter 194mm, diameter 219mm. They almost ...