The X-Type, or 4-point contact, ball bearing is ideal for moment loading. X-Type bearings are designed with gothic arch raceways creating 4 contact points between the balls and the raceways. This design is excellent for moment loading and reversing axial loading.
The X-Type bearing can be used for other light loading conditions, but is not recommended in place of the C- or A-Type bearing for pure radial loads. When specifying this type of bearing for use with axial or moment loads combined with radial loads application speed (rpm) is a real concern.