Requisite minimum load
The correlation between load and service life is less evident at very light loads. Other failure mechanisms than fatigue are determining.
To achieve satisfactory operation, ball and roller bearings must always be subjected to a given minimum load. A general "rule of thumb" indicates that minimum loads corresponding to 0,02 C should be imposed on roller bearings and minimum loads corresponding to 0,01 C on ball bearings. The importance of applying this minimum load increases where accelerations in the bearing are high, and where speeds are in the region of 50% or more of the limiting speeds quoted in the product tables, see section Speeds and vibration. If minimum load requirements cannot be met,
Recommendations for calculating the requisite minimum loads for the different bearing types are provided in the product sections.