SANY Crane Slewing Bearing and Slew Reducer

Slewing bearing, slew reducer and slew motor parts for SANY STC-series truck cranes. The bearing is sized to load moment, not to the tonnage badge. On SANY's published figures the export STC250 carries 962 kN·m on the base boom, the STC500 1,774 kN·m and the STC800 2,560 kN·m, so raceway diameter, ball size and bolt pattern are a size class apart across the three; the later STC800S is rated at 2,822 to 2,958 kN·m depending on counterweight and is a different build again. The STC250 brochure specifies a single-row ball slewing ring. Maximum slewing speed is 2.0 r/min on the STC500 and STC800 and 2.0 to 2.2 r/min across STC250 brochure editions, while domestic C5 builds of the STC250 list 2.6 to 2.8 r/min — the reducer and motor are matched to that speed. A slewing bearing is a structural safety part and we quote it only against the superstructure serial number. Before ordering one for a crane that slews roughly, measure the tilt clearance with the boom loaded and unloaded and compare it with the wear limit in the manual: jerky starts and stops are more often the slew brake, the slewing buffer valve or the reducer than the bearing.