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When a worn or undersized ball causes play in a bearing, vibration in a pivot, or drag in a derailleur, finding the exact replacement diameter is the only fix. Machinists, bicycle mechanics, and DIY repair technicians who need chrome steel balls in precise sub-millimeter increments know how frustrating it is to source the right size. These G10-grade chrome steel balls are stocked in a wide diameter range — 1.0 mm through 4.0 mm — with increments as fine as 0.002 mm, so you can match the original spec without compromise.
Each ball is manufactured from high-carbon chromium steel (typically equivalent to AISI 52100 / GCr15), hardened and ground to G10 tolerance class. Diameters span 1.0 mm to 4.0 mm (approximately 0.039 in to 0.157 in), with surface roundness and diameter variation held to within ±0.0025 mm at G10 grade. The bright, smooth surface finish reduces friction and resists corrosion in lightly lubricated environments.
Typical applications include bicycle headset and bottom-bracket bearing replacement, skateboard and inline-skate bearing service, small instrument bearings, check-valve seats in pneumatic and hydraulic fittings, and precision jig or fixture locating balls. The multi-pack options (1, 50, 100, 200, 500 pieces) suit both single-repair jobs and workshop stock replenishment.
Diameter variation and sphericity held to G10 class — suitable for precision bearing replacement and instrument applications requiring tight dimensional control.
Available from 1.0 mm to 4.0 mm with increments as fine as 0.002 mm, covering standard metric sizes and many imperial-equivalent diameters in a single product listing.
Made from high-carbon chromium steel (GCr15 / AISI 52100 equivalent) — the industry-standard alloy for rolling-element bearings, offering a balance of hardness, toughness, and wear resistance.
Precision-ground and polished surface finish minimises friction in rolling contact, reduces noise, and extends service life in lubricated bearing assemblies.
Choose from 1, 50, 100, 200, or 500 pieces per order. Single-piece options let you trial-fit a size; bulk packs reduce per-unit cost for workshop restocking.
Sized to replace balls in bicycle headsets, bottom brackets, pedal bearings, and hub cones, as well as skateboard bearings, small instrument pivots, and check-valve seats.
| Material | High-carbon chromium steel (GCr15 / AISI 52100 equivalent) |
|---|---|
| Grade | G10 |
| Diameter Range | 1.0 mm – 4.0 mm (approx. 0.039 in – 0.157 in) |
| Diameter Increments | As fine as 0.002 mm (see variant options) |
| Diameter Tolerance | ±0.0025 mm (G10 class) |
| Surface Finish | Precision ground and polished |
| Hardness | See variant options |
| Pack Size Options | 1 Pcs / 50 Pcs / 100 Pcs / 200 Pcs / 500 Pcs |
| Corrosion Resistance | Moderate (suitable for lubricated environments; not for immersion or food-grade use) |
| Typical Applications | Bicycle bearings, skateboard bearings, instrument pivots, check valves, precision fixtures |
Use a digital micrometer or a ball-gauge set to measure the existing balls or the bearing race groove. Measure at least three points around the ball and take the average. For bicycle bearings, the ball size is often stamped on the cone or listed in the bike manufacturer's service manual. When in doubt, measure — do not rely on visual estimation, as differences of 0.002 mm can affect bearing preload.
G10 is an ABMA/ISO tolerance grade for precision balls. It specifies that the diameter variation (difference between largest and smallest diameter on one ball) and the lot diameter variation are both within 0.25 µm (0.00025 mm). G10 is suitable for most bicycle bearings, skateboard bearings, and general instrument applications. For ultra-precision spindle bearings or aerospace use, G3 or G5 grade may be required.
Yes, chrome steel balls can run in stainless steel races. However, if the entire bearing assembly must be corrosion-resistant (e.g., marine, food-processing, or wet environments), you should use stainless steel balls instead. Chrome steel balls will surface-rust if exposed to moisture without lubrication for extended periods.
Yes. These are a common replacement for loose-ball bicycle headsets and cup-and-cone bottom brackets. Typical headset ball sizes range from 3/16 in (4.763 mm) down to 1/8 in (3.175 mm), and many metric equivalents are available in this listing. Always count the existing balls and measure one before ordering to confirm the correct diameter and quantity.
Store in a sealed container with a light coating of machine oil or anti-corrosion spray. Keep away from moisture and humidity. If balls will be stored for more than a few months, consider wrapping them in oil-impregnated paper or placing a silica-gel desiccant packet in the storage container.
Many bearing standards use both metric and imperial dimensions. For example, 3.175 mm is the exact metric equivalent of 1/8 inch, while 3.18 mm is a rounded metric size. In a precision bearing, substituting one for the other can change preload and affect bearing life. Always match the diameter to the original specification — measure with a micrometer rather than selecting by eye.
For a single repair (e.g., one bicycle headset), the 1-piece or 50-piece pack is usually sufficient — most headsets use 18–22 balls per race. For workshop use or if you service multiple bikes or machines, the 100, 200, or 500-piece packs offer a lower per-ball cost and ensure you always have the right size on hand.
