{"product_id":"gcr15-steel-ball-bearing-g10-bicycle-replacement-5-9mm-6-03mm","title":"Durable Bicycle Gcr15 Steel Ball Bearing G10 Replacement Bearings 5.9mm-6.03mm","description":"\u003cdiv class=\"hdiy-desc\"\u003e\n\u003cdiv class=\"hdiy-overview\"\u003e\n\u003ch2\u003eGCR15 Steel Ball Bearings — G10 Grade Bicycle Replacement Balls, 5.9mm to 6.03mm\u003c\/h2\u003e\n\u003cp\u003eWhen a worn or pitted bearing ball causes your bicycle hub, bottom bracket, or headset to feel rough and imprecise, finding a replacement with the right diameter tolerance is critical. Mechanics, cyclists, and workshop technicians who need exact-size steel balls to restore smooth rotation rely on dimensionally consistent, hardened rolling elements — not generic loose balls that introduce play or noise.\u003c\/p\u003e\n\u003cp\u003eThese GCR15 chrome steel ball bearings are manufactured to G10 grade, offering a surface roughness and roundness tolerance suitable for bicycle drivetrain and steering applications. Available in diameters from 5.90mm (~0.232\") to 6.03mm (~0.237\"), each size is sold separately so you can match the exact specification of your original bearing assembly. Packing options include 100-piece bags, 1 kg bulk, and 2.8 kg bulk for workshop or fleet use.\u003c\/p\u003e\n\u003cp\u003eTypical applications include bicycle cup-and-cone hub bearings, threaded bottom bracket cartridges, loose-ball headsets, and pedal axle bearings — anywhere a GCR15 steel ball bearing in the 6mm nominal range is required. The tight diameter increments (0.01mm steps) make these GCR15 steel ball bearings especially useful when selecting an oversize replacement to compensate for worn bearing races.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"hdiy-compat\"\u003e\n\u003cspan class=\"hdiy-compat-icon\"\u003e🔧\u003c\/span\u003e \u003cstrong\u003eCompatibility:\u003c\/strong\u003e Designed for cup-and-cone bicycle hubs, loose-ball headsets, threaded bottom brackets, and pedal axle assemblies requiring a ~6mm nominal GCR15 steel ball. Verify your existing ball diameter before selecting a variant.\u003c\/div\u003e\n\u003cdiv class=\"hdiy-features\"\u003e\n\u003ch2\u003e✅ Key Features of These GCR15 Steel Ball Bearings\u003c\/h2\u003e\n\u003cdiv class=\"hdiy-list\"\u003e\n\u003cdiv\u003e\n\u003cspan class=\"hdiy-icon\"\u003e⚙️\u003c\/span\u003e\u003cstrong\u003eG10 Grade Tolerance\u003c\/strong\u003e\u003cbr\u003eRoundness and surface finish meet G10 specifications, ensuring consistent rolling contact and reduced vibration in bicycle bearing assemblies.\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🔩\u003c\/span\u003e\u003cstrong\u003eGCR15 Chrome Steel Construction\u003c\/strong\u003e\u003cbr\u003eGCR15 bearing steel provides a hardness of approximately 60–65 HRC after heat treatment, resisting deformation under the cyclic loads typical of bicycle hubs and bottom brackets.\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cspan class=\"hdiy-icon\"\u003e📏\u003c\/span\u003e\u003cstrong\u003ePrecision Diameter Steps (0.01mm increments)\u003c\/strong\u003e\u003cbr\u003eSizes from 5.90mm to 6.03mm in 0.01mm steps allow you to select an exact or deliberate oversize replacement to restore proper bearing preload in worn races.\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cspan class=\"hdiy-icon\"\u003e📦\u003c\/span\u003e\u003cstrong\u003eFlexible Pack Quantities\u003c\/strong\u003e\u003cbr\u003eAvailable in 100-piece bags for single-bike service, 1 kg bulk for workshop stock, and 2.8 kg bulk for fleet maintenance or resale — reducing per-unit cost at volume.\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🛡️\u003c\/span\u003e\u003cstrong\u003eCorrosion-Resistant Surface Finish\u003c\/strong\u003e\u003cbr\u003eThe polished chrome steel surface resists light moisture exposure encountered in road and trail cycling conditions, maintaining dimensional integrity over repeated service intervals.\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🔄\u003c\/span\u003e\u003cstrong\u003eDirect Drop-In Replacement\u003c\/strong\u003e\u003cbr\u003eLoose ball format matches the assembly method of cup-and-cone hubs and loose-ball headsets — no special tooling required beyond standard cone wrenches and grease.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"hdiy-table-wrap\"\u003e\n\u003ch2\u003e📐 Technical Specifications — GCR15 Steel Ball Bearings\u003c\/h2\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eMaterial\u003c\/th\u003e\n\u003ctd\u003eGCR15 Chrome Steel\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eGrade\u003c\/th\u003e\n\u003ctd\u003eG10\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eDiameter Range\u003c\/th\u003e\n\u003ctd\u003e5.90mm – 6.03mm (approx. 0.232\" – 0.237\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eDiameter Increment\u003c\/th\u003e\n\u003ctd\u003e0.01mm steps (see variant options)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eNominal Size\u003c\/th\u003e\n\u003ctd\u003e~6mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eSurface Hardness\u003c\/th\u003e\n\u003ctd\u003eTypically 60–65 HRC (GCR15 heat-treated)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eSurface Finish\u003c\/th\u003e\n\u003ctd\u003ePolished chrome steel\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eBall Type\u003c\/th\u003e\n\u003ctd\u003eLoose (uncaged)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003ePacking Options\u003c\/th\u003e\n\u003ctd\u003e100pcs \/ 1kg \/ 2.8kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eTypical Application\u003c\/th\u003e\n\u003ctd\u003eBicycle hubs, headsets, bottom brackets, pedal axles\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eWeight (per pack)\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"hdiy-faq\"\u003e\n\u003ch2\u003e❓ Frequently Asked Questions\u003c\/h2\u003e\n\u003cdetails\u003e\n\u003csummary\u003eHow do I know which diameter to choose for my bicycle hub?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eRemove one of the existing balls from your hub bearing race and measure it with a digital caliper. Match that measurement to the available diameter options. If your races show wear grooves, you may choose the next size up (e.g., 5.98mm instead of 5.95mm) to restore proper preload and eliminate play.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eWhat does G10 grade mean for ball bearings?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eG10 is an ISO 3290 grade designation indicating that the ball's diameter deviation, spherical error, and surface roughness all fall within defined tolerances — specifically a maximum deviation of 0.25µm for roundness. G10 is suitable for bicycle drivetrain and steering applications where smooth, consistent rolling is required without the cost of precision instrument-grade balls.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eAre GCR15 steel balls corrosion-resistant enough for wet riding conditions?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eGCR15 chrome steel offers moderate corrosion resistance due to its chromium content, but it is not stainless steel. For wet or muddy riding, apply a quality bearing grease (e.g., lithium-based or waterproof grease) and re-grease at regular service intervals. In highly corrosive environments, consider stainless steel balls as an alternative.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eCan I use these balls in a cartridge bearing or sealed bearing unit?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eThese are loose (uncaged) balls intended for cup-and-cone style assemblies — such as traditional bicycle hubs, threaded headsets, and loose-ball bottom brackets. Sealed cartridge bearings are factory-assembled units and are not serviceable with individual loose balls. If your bicycle uses cartridge bearings, you will need a replacement cartridge instead.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eHow many balls do I need per hub or headset?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eThe count varies by component. A typical front hub uses 9–10 balls per side (18–20 total), a rear hub uses 9 balls per side (18 total), and a threaded headset uses 18–22 balls across both cups. Check your component's service manual or count the existing balls before ordering. The 100-piece pack is sufficient for a full hub service on most bikes.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eWhat is the difference between the 1kg and 2.8kg bulk packs?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eBoth bulk packs contain the same G10 GCR15 steel balls — the difference is quantity. A 1kg pack is suited for workshop stock covering multiple service jobs, while the 2.8kg pack offers a lower per-ball cost for bicycle shops, fleet maintenance operations, or resellers who service a high volume of bikes regularly.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eIs it safe to mix balls of slightly different diameters in the same bearing race?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eNo. All balls in a single bearing race must be the same diameter. Mixing sizes causes uneven load distribution, accelerated race wear, and rough rolling. Always replace all balls in a race with the same diameter variant, and use a fresh application of bearing grease during reassembly.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"hdiy-cta\"\u003e🛒 Select your Diameter and Packing Qty above, then add to cart.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"HomeDIYer","offers":[{"title":"5.9mm \/ 100pcs","offer_id":52410324812050,"sku":"LFL2024GANGZHU2844x100","price":6.76,"currency_code":"USD","in_stock":true},{"title":"5.95mm \/ 100pcs","offer_id":52410324844818,"sku":"LFL2024GANGZHU2845x100","price":6.85,"currency_code":"USD","in_stock":true},{"title":"5.98mm \/ 100pcs","offer_id":52410324877586,"sku":"LFL2024GANGZHU2846x100","price":6.91,"currency_code":"USD","in_stock":true},{"title":"6mm \/ 100pcs","offer_id":52410324910354,"sku":"LFL2024GANGZHU2847x100","price":6.91,"currency_code":"USD","in_stock":true},{"title":"6.01mm \/ 100pcs","offer_id":52410324943122,"sku":"LFL2024GANGZHU2848x100","price":6.91,"currency_code":"USD","in_stock":true},{"title":"6.02mm \/ 100pcs","offer_id":52410324975890,"sku":"LFL2024GANGZHU2849x100","price":7.02,"currency_code":"USD","in_stock":true},{"title":"6.03mm \/ 100pcs","offer_id":52410325008658,"sku":"LFL2024GANGZHU2850x100","price":7.02,"currency_code":"USD","in_stock":true},{"title":"5.90mm \/ 1kg","offer_id":52410325041426,"sku":"LFL2024GANGZHU2851x1","price":39.92,"currency_code":"USD","in_stock":true},{"title":"5.95mm \/ 1kg","offer_id":52410325074194,"sku":"LFL2024GANGZHU2852x1","price":39.92,"currency_code":"USD","in_stock":true},{"title":"5.98mm \/ 1kg","offer_id":52410325106962,"sku":"LFL2024GANGZHU2853x1","price":39.92,"currency_code":"USD","in_stock":true},{"title":"6.00mm \/ 1kg","offer_id":52410325139730,"sku":"LFL2024GANGZHU2854x1","price":39.92,"currency_code":"USD","in_stock":true},{"title":"6.01mm \/ 1kg","offer_id":52410325172498,"sku":"LFL2024GANGZHU2855x1","price":39.92,"currency_code":"USD","in_stock":true},{"title":"6.02mm \/ 1kg","offer_id":52410325205266,"sku":"LFL2024GANGZHU2856x1","price":39.92,"currency_code":"USD","in_stock":true},{"title":"6.03mm \/ 1kg","offer_id":52410325238034,"sku":"LFL2024GANGZHU2857x1","price":39.92,"currency_code":"USD","in_stock":true},{"title":"5.90mm \/ 2.8kg","offer_id":52410325270802,"sku":"LFL2024GANGZHU2858x1","price":106.64,"currency_code":"USD","in_stock":true},{"title":"5.95mm \/ 2.8kg","offer_id":52410325303570,"sku":"LFL2024GANGZHU2859x1","price":106.64,"currency_code":"USD","in_stock":true},{"title":"5.98mm \/ 2.8kg","offer_id":52410325336338,"sku":"LFL2024GANGZHU2860x1","price":106.64,"currency_code":"USD","in_stock":true},{"title":"6.00mm \/ 2.8kg","offer_id":52410325369106,"sku":"LFL2024GANGZHU2861x1","price":106.64,"currency_code":"USD","in_stock":true},{"title":"6.01mm \/ 2.8kg","offer_id":52410325401874,"sku":"LFL2024GANGZHU2862x1","price":106.64,"currency_code":"USD","in_stock":true},{"title":"6.02mm \/ 2.8kg","offer_id":52410325434642,"sku":"LFL2024GANGZHU2863x1","price":106.64,"currency_code":"USD","in_stock":true},{"title":"6.03mm \/ 2.8kg","offer_id":52410325467410,"sku":"LFL2024GANGZHU2864x1","price":106.64,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0884\/8936\/1682\/files\/Picture4of6_23a3bcab-3ae6-42a7-9687-95d5be561f2f.jpg?v=1782406368","url":"https:\/\/homediyer.com\/products\/gcr15-steel-ball-bearing-g10-bicycle-replacement-5-9mm-6-03mm","provider":"HomeDIYer","version":"1.0","type":"link"}