Equivalent Static Load

The equivalent static load P₀ is a theoretical value (according to ISO 76). It is a radial load for radial bearings and an axial and centrical load for thrust bearings. P₀ causes the same stress at the center of the most heavily pressurized contact area of the rolling element or raceway as the actual load combination.

P0	equivalent static load [N]
Fr	radial load [N]
Fa	axial load [N]
X0	radial factor
Y0	thrust factor

In the following three tables, the calculation factors X₀ and Y₀ are summarized for single and double row deep groove ball bearings and angular contact ball bearings.

Table 5: Calculation factors X₀ and Y₀ for single and double row radial ball bearings

* P₀ is always ≥ F_r otherwise P₀ = F_r instead of Formula 10


Table 6: Calculation factors X₀ and Y₀ for single row angular contact ball bearings

* P₀ is always ≥ F_r otherwise P₀ = F_r instead of Formula 10


Table 7: Calculation factors X₀ and Y₀ for double row angular contact ball bearings

* for all load conditions

Static Load Safety Factor

The static load safety factor s₀ is the ratio between the basic static load rating C₀ and the highest occurring load P₀ (according to ISO 76).

C0	basic static load rating [N]
P0	equivalent static bearing load [N]
s0	static load safety factor

For our bearing types, the basic static load rating C₀ for single and double row deep groove ball bearings as well as single and double row angular contact ball bearings are listed in the product tables.

The basic static load ratings listed in these tables are based on our standard bearing steel and our standard heat treatment. Load ratings of alternative bearing steels can be obtained from us upon request.

Guideline values based on experience are given in Table 8 for the static load safety factor s₀ for ball bearings for various types of requirements with respect to smooth running.

Table 8: Factor of safety for static loading


At elevated temperatures, the basic static load rating is reduced.

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