Conveyor Idler Bearing Life Calculator

L10 is the life that 90% of identical bearings reach under the same load and speed before the first sign of fatigue — equivalently, a 10% failure probability. Median life is roughly 5× L10. It is a statistical fatigue life, not a guarantee for any single bearing.

Take belt weight plus material burden per metre (kg/m), multiply by the idler spacing (m) and g to get newtons per idler set, then split per roll — the centre roll of a 3-roll trough carries roughly 60–70%. Under transfer points, add impact factors of 2–4×. That number, in kN, is your P for this calculator.

C (basic dynamic load rating) is printed in every bearing datasheet — for example a 6204 ball bearing (C = 12.7 kN) in a 133 mm idler roll at ~540 rpm belt speed. P is the equivalent dynamic load: for pure radial load it is simply the radial force; with combined radial + axial load use P = X·Fr + Y·Fa with X and Y from the datasheet.

Because L10 assumes clean lubricant, correct fit and alignment. In practice most bearings die of lubrication failure, contamination, misalignment or fitting damage rather than fatigue. If yours fail early, check the actual load path and the grease before blaming the bearing.

Use p = 3 for ball bearings and p = 10/3 for roller bearings (cylindrical, spherical, taper). Rollers carry load on a line contact rather than a point, so their life is less sensitive to load — that is what the higher exponent encodes.