# Loads

 Minimum load For additional information → Requisite minimum load Minimum axial load for single bearings and bearing pairs arranged in tandem: Minimum radial load for bearing pairs arranged back-to-back or face-to-face: Perform calculations Equivalent dynamic bearing load For additional information → Equivalent dynamic bearing load, P Single bearings and bearing pairs arranged in tandem: Fa/Fr ≤ e → P = Fr Fa/Fr > e → P = X Fr + Y2 Fa When determining the axial load Fa, refer to Calculating the axial load for bearings mounted singly or paired in tandem. Bearing pairs arranged back-to-back or face-to-face: Fa/Fr ≤ e → P = Fr + Y1 Fa Fa/Fr > e → P = X Fr + Y2 Fa Perform calculations Equivalent static bearing load For additional information → Equivalent static load Single bearings and bearing pairs arranged in tandem: P0 = 0,5 Fr + Y0 Fa P0 < Fr → P0 = Fr When determining the axial load Fa, refer to Calculating the axial load for bearings mounted singly or paired in tandem. Bearing pairs arranged back-to-back or face-to-face: P0 = Fr + Y0 Fa
Calculating the axial load for bearings mounted singly or paired in tandem

When a radial load is applied to a single row angular contact ball bearing, the load is transmitted from one raceway to the other at an angle to the bearing axis and an internal axial load is induced. This must be considered when calculating the equivalent bearing loads for bearings in adjusted arrangements consisting of two single bearings and/or bearing pairs arranged in tandem.

The equations (table 1) are only valid if the bearings have identical contact angles and are adjusted against each other to practically zero clearance, but without any preload. In the table, bearing A is subjected to a radial load FrA and bearing B to a radial load FrB. Both FrA and FrB are always considered positive, even when they act in the direction opposite to that shown in the figures. The radial loads act at the pressure centres of the bearings (distance a, refer to product table).

These calculations can easily be done with SKF's online calculation tools. When the bearings are adjusted with clearance or preload, or when bearings with different contact angles are used, the equations become more complex and can be done using the SKF SimPro platform (SKF SimPro Quick).
Load carrying capacity of bearing pairs

The values for basic load ratings and fatigue load limits listed in the product table apply to single bearings. For universally matchable bearings mounted immediately adjacent to each other, the following values apply:

• basic dynamic load rating for standard bearings in all arrangements and for SKF Explorer bearings in a back-to-back or face-to-face arrangement
Cpair = 1,62 Csingle bearing

• basic dynamic load rating for SKF Explorer bearings in a tandem arrangement
Cpair = 2 Csingle bearing

• basic static load rating
C0 pair = 2 C0single bearing

• fatigue load limit
Pu pair = 2 Pu single bearing

## Symbols

 A minimum axial load factor (→ product table) dm bearing mean diameter [mm] = 0,5 (d + D) e calculation factor (→ product table) Fa axial load [kN] Fam minimum axial load [kN] Fr radial load [kN] Frm minimum radial load [kN] kr minimum radial load factor (→ product table) n rotational speed [r/min] P equivalent dynamic bearing load [kN] P0 equivalent static bearing load [kN] X, Y0, Y1, Y2 calculation factors (→ product table) ν actual operating viscosity of the lubricant [mm2/s]