1KG Bicycle Gcr15 Steel Ball Bearing Replacement Bearings13.5 14.288 - 19.05mm

Measure the diameter of your existing balls using a micrometer or digital caliper. Alternatively, check your hub, headset, or bottom bracket manufacturer's service manual for the specified ball size. Common road bike hub sizes fall between 13.5 mm and 15.875 mm, while larger cruiser or BMX hubs may use 19.05 mm or 19.844 mm balls. When in doubt, measure the bearing cup seat width and count the existing balls to cross-reference with standard sizing charts.

GCr15 is a high-carbon chromium bearing steel grade (roughly equivalent to AISI 52100) widely used for precision rolling elements. The high carbon content (approximately 0.95–1.05%) and chromium addition (1.3–1.65%) allow the steel to be through-hardened to high Rockwell hardness values, giving the balls excellent wear resistance, fatigue strength, and dimensional stability under cyclic loading — all critical properties for bicycle bearing applications.

Yes. These balls are dimensionally matched to standard loose-ball and caged retainer bearing assemblies used in bicycle hubs, headsets, and bottom brackets. Confirm the ball diameter matches your retainer's pocket size before installing. If you are replacing loose balls in a cup-and-cone hub, simply match the diameter and repack with fresh bearing grease.

Store unused balls in a sealed container away from moisture and direct contact with dissimilar metals. A light coating of bearing grease or rust-preventive oil on stored balls will extend shelf life significantly. Avoid storing in humid environments or near solvents that could degrade any protective surface treatment.

GCr15 steel balls in these diameter ranges are also used in general mechanical assemblies, drawer slides, and light industrial bearing seats where the same diameter is specified. However, always verify the required hardness, surface finish grade, and dimensional tolerance for your specific application before substituting. These balls are optimized and marketed for bicycle bearing service.

The ball count per kilogram varies by diameter — smaller diameter balls are lighter individually, so a 1 kg pack of 13.5 mm balls will contain significantly more pieces than a 1 kg pack of 19.844 mm balls. If you need an exact count for a specific service job, contact us to confirm the approximate quantity for your chosen diameter.

A lithium-based or synthetic bicycle-specific bearing grease (such as Phil Wood Waterproof Grease or equivalent) is recommended. Apply a moderate layer to the bearing cup, seat the balls, and add a thin top coat before installing the cone or cover. Avoid petroleum-based greases that may degrade rubber seals in adjacent components.