Hirobo HI2500067 4 x 13 x 5 mm Ball Bearings (2 pcs)  [HI2500067]

Small-diameter bearings for rotor and gearbox shafts

This Hirobo replacement set includes two 4 x 13 x 5 mm ball bearings, carrying the #624ZZ identifier, designed for use in compact RC helicopter linkages and drivetrain subassemblies that require small rolling elements.

These parts are general-fit service bearings rather than model-specific spares, so confirm the 4 x 13 x 5 mm inner, outer, and width measurements against your shaft and housing before fitting.

During installation press the bearing evenly into its bore and avoid imposing side loads. Protect mating surfaces from dust and grit, and when removing old bearings use correct pulling tools to prevent shaft and gear damage. Replacing worn bearings decreases play and helps preserve smooth response in rotors and gearboxes.