Full definition
Number of revolutions —or hours at constant speed— that 90% of an identical group of bearings will complete without surface fatigue failure. ISO 281 formula: L10 = (C/P)^p × 10⁶ rev, where C = dynamic load capacity (kN), P = equivalent dynamic load (kN), p = 3 for ball bearings / 10/3 for roller bearings. Modified life Lnm accounts for lubrication, contamination and material. ISO 281 standard.