IMO is one of the world's leading manufacturers of single-row and double-row ball slewing rings used as blade and yaw bearings, as well as for azimuth gear rims to a diameter of 5,200 mm. ... Roller slewing rings from IMO are in use as single main bearings for gear- and shaftless wind turbines.we produce standard versions of ball slewing rings, roller slewing rings, and ball-roller combination slewing rings with dimensions ranging from 100 to 6,000 mm.  Today, our ready-to-install units with spur gear unit or worm drive are available in a wide range of standard series.