{"product_id":"1kg-bicycle-45-steel-ball-bearing-g100-replacement-bearings-6-90mm-8-05mm","title":"1KG Bicycle 45# Steel Ball Bearing G100 Replacement Bearings Size: 6.90mm-8.05mm","description":"\u003cdiv class=\"hdiy-desc\"\u003e\n\u003cdiv class=\"hdiy-overview\"\u003e\n\u003ch2\u003eBicycle Steel Ball Bearings G100 — Precision Replacement for Smooth, Reliable Rolling\u003c\/h2\u003e\n\u003cp\u003eWhen a worn or pitted ball bearing turns a smooth ride into a grinding, sluggish one, finding the exact replacement diameter matters. Cyclists, mechanics, and workshop technicians who maintain road bikes, mountain bikes, and BMX builds rely on consistent, accurately sized steel ball bearings to restore hub, headset, and bottom bracket performance. These 45# steel bicycle ball bearings are available in 22 precise diameter options spanning 6.90mm to 8.05mm (approximately 0.272\" to 0.317\"), so you can match the exact spec your bearing race requires.\u003c\/p\u003e\n\u003cp\u003eEach order contains 1 kg of G100-grade 45# carbon steel ball bearings in your chosen diameter. G100 denotes a roundness and surface finish tolerance of ±0.0025mm, meeting ISO 3290 Grade 100 standards. The balls are ground and lapped to a smooth, consistent finish suited for bicycle bearing applications where load capacity and low rolling resistance are both required.\u003c\/p\u003e\n\u003cp\u003eThese bearings are well suited for bicycle hub overhauls where loose-ball cup-and-cone systems need a full complement refresh, headset rebuilds on threaded or threadless forks, and bottom bracket servicing on older square-taper or cup-and-cone style cranks. The 1 kg bulk pack provides enough quantity for multiple service jobs or a full workshop stock of a single size.\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 loose-ball cup-and-cone bicycle bearing systems including front and rear hubs, headsets, and bottom brackets. Verify your bearing race diameter before selecting a size. Not intended for sealed cartridge bearing replacements.\u003c\/div\u003e\n\u003cdiv class=\"hdiy-features\"\u003e\n\u003ch2\u003e✅ Key Features of These Bicycle Steel Ball Bearings\u003c\/h2\u003e\n\u003cul class=\"hdiy-list\"\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e⚙️\u003c\/span\u003e \u003cstrong\u003eG100 Grade Precision:\u003c\/strong\u003e Manufactured to ISO 3290 Grade 100 tolerance — roundness deviation ≤0.0025mm — for consistent rolling contact and even load distribution across the bearing race.\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🔩\u003c\/span\u003e \u003cstrong\u003e45# Carbon Steel Construction:\u003c\/strong\u003e Made from 45# medium-carbon steel, offering a balance of surface hardness after heat treatment and core toughness suitable for the cyclic loads found in bicycle bearing applications.\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e📏\u003c\/span\u003e \u003cstrong\u003e22 Diameter Options (6.90mm–8.05mm):\u003c\/strong\u003e Covers the most common loose-ball sizes used in bicycle hubs, headsets, and bottom brackets, with increments as fine as 0.01mm for accurate fitment.\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e⚖️\u003c\/span\u003e \u003cstrong\u003e1 kg Bulk Pack:\u003c\/strong\u003e Sold by weight rather than a fixed count, giving you a practical workshop quantity — typically enough for several full hub rebuilds depending on the diameter selected.\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🔄\u003c\/span\u003e \u003cstrong\u003eSmooth Lapped Surface Finish:\u003c\/strong\u003e Each ball is ground and lapped to reduce surface roughness, minimising friction and wear against the bearing cup and cone surfaces during operation.\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🗂️\u003c\/span\u003e \u003cstrong\u003eDirect Drop-In Replacement:\u003c\/strong\u003e Sized to match standard loose-ball bicycle bearing specifications, making these a straightforward replacement during routine hub, headset, or bottom bracket servicing without modification.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"hdiy-table-wrap\"\u003e\n\u003ch2\u003e📐 Technical Specifications — Bicycle Ball Bearings\u003c\/h2\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eMaterial\u003c\/th\u003e\n\u003ctd\u003e45# Carbon Steel\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eGrade\u003c\/th\u003e\n\u003ctd\u003eG100 (ISO 3290 Grade 100)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eDiameter Range\u003c\/th\u003e\n\u003ctd\u003e6.90mm – 8.05mm (approx. 0.272\" – 0.317\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eDiameter Increments\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eRoundness Tolerance\u003c\/th\u003e\n\u003ctd\u003e≤ 0.0025mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003ePack Weight\u003c\/th\u003e\n\u003ctd\u003e1 kg per order\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFinish\u003c\/th\u003e\n\u003ctd\u003eGround and lapped\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eApplication\u003c\/th\u003e\n\u003ctd\u003eBicycle hubs, headsets, bottom brackets (cup-and-cone \/ loose-ball systems)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eBearing Type\u003c\/th\u003e\n\u003ctd\u003eLoose ball (not pre-assembled cartridge)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eQuantity per Pack\u003c\/th\u003e\n\u003ctd\u003eSee variant options (varies by diameter)\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 find the correct ball bearing diameter for my bicycle?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eRemove the existing balls from your hub, headset, or bottom bracket and measure one with a digital calliper. Match that measurement to the diameter option listed in the variant selector. If the existing balls are worn, consult your bicycle's service manual or the bearing race manufacturer's specification for the nominal ball diameter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eWhat does G100 grade mean for ball bearings?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eG100 refers to the ISO 3290 precision grade, indicating that the maximum deviation from a perfect sphere (roundness error) is no greater than 0.0025mm (2.5 micrometres). This level of precision is appropriate for bicycle bearing applications where smooth rolling and consistent load distribution are required.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eAre these bearings suitable for sealed cartridge bearing systems?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eNo. These are loose balls intended for cup-and-cone style bearing systems where individual balls sit directly in a bearing race. Sealed cartridge bearings are pre-assembled units and cannot be repacked with loose balls. Check your hub or headset design before ordering.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eHow many ball bearings are in a 1 kg pack?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eThe count varies by diameter — smaller balls are lighter, so a 1 kg pack contains more of them. As a general reference, 7mm steel balls weigh approximately 1.4g each, yielding roughly 700 balls per kilogram. Larger diameters will yield fewer balls per kilogram. The 1 kg pack is designed to provide a practical workshop quantity for multiple service jobs.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eWill 45# carbon steel bearings rust if exposed to moisture?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003e45# carbon steel is not stainless and will oxidise if left exposed to moisture without lubrication. For bicycle applications, always pack the bearing race with a suitable grease before installation. Store unused balls in a dry, sealed container. If your application involves frequent water exposure, consider whether a stainless steel grade would be more appropriate for your use case.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eCan I mix different diameter balls 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 creates uneven load distribution, accelerates wear on the race surfaces, and can cause the bearing to run roughly or fail prematurely. Always replace a full complement of balls with a consistent diameter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eHow do I decide between adjacent sizes, for example 7.00mm vs 7.01mm?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eMeasure your existing balls with a digital calliper accurate to 0.01mm or better. Match the measured diameter as closely as possible. If the race shows wear, the original nominal size specified by the bicycle or component manufacturer is the correct reference. When in doubt, contact us to confirm the correct size for your specific component.\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":"6.90mm \/ 1kg","offer_id":52409666044178,"sku":"LFL2024GANGZHU3952x1","price":66.97,"currency_code":"USD","in_stock":true},{"title":"6.95mm \/ 1kg","offer_id":52409666076946,"sku":"LFL2024GANGZHU3953x1","price":66.97,"currency_code":"USD","in_stock":true},{"title":"6.98mm \/ 1kg","offer_id":52409666109714,"sku":"LFL2024GANGZHU3954x1","price":66.97,"currency_code":"USD","in_stock":true},{"title":"7.00mm \/ 1kg","offer_id":52409666142482,"sku":"LFL2024GANGZHU3955x1","price":66.97,"currency_code":"USD","in_stock":true},{"title":"7.01mm \/ 1kg","offer_id":52409666175250,"sku":"LFL2024GANGZHU3956x1","price":66.97,"currency_code":"USD","in_stock":true},{"title":"7.02mm \/ 1kg","offer_id":52409666208018,"sku":"LFL2024GANGZHU3957x1","price":66.97,"currency_code":"USD","in_stock":true},{"title":"7.03mm \/ 1kg","offer_id":52409666240786,"sku":"LFL2024GANGZHU3958x1","price":66.97,"currency_code":"USD","in_stock":true},{"title":"7.04mm \/ 1kg","offer_id":52409666273554,"sku":"LFL2024GANGZHU3959x1","price":67.5,"currency_code":"USD","in_stock":true},{"title":"7.90mm \/ 1kg","offer_id":52409666306322,"sku":"LFL2024GANGZHU3960x1","price":66.38,"currency_code":"USD","in_stock":true},{"title":"7.92mm \/ 1kg","offer_id":52409666339090,"sku":"LFL2024GANGZHU3961x1","price":66.38,"currency_code":"USD","in_stock":true},{"title":"7.938mm \/ 1kg","offer_id":52409666371858,"sku":"LFL2024GANGZHU3962x1","price":66.38,"currency_code":"USD","in_stock":true},{"title":"7.95mm \/ 1kg","offer_id":52409666404626,"sku":"LFL2024GANGZHU3963x1","price":66.38,"currency_code":"USD","in_stock":true},{"title":"7.96mm \/ 1kg","offer_id":52409666437394,"sku":"LFL2024GANGZHU3964x1","price":66.38,"currency_code":"USD","in_stock":true},{"title":"7.97mm \/ 1kg","offer_id":52409666470162,"sku":"LFL2024GANGZHU3965x1","price":66.38,"currency_code":"USD","in_stock":true},{"title":"7.98mm \/ 1kg","offer_id":52409666502930,"sku":"LFL2024GANGZHU3966x1","price":66.38,"currency_code":"USD","in_stock":true},{"title":"7.99mm \/ 1kg","offer_id":52409666535698,"sku":"LFL2024GANGZHU3967x1","price":66.38,"currency_code":"USD","in_stock":true},{"title":"8.00mm \/ 1kg","offer_id":52409666568466,"sku":"LFL2024GANGZHU3968x1","price":66.38,"currency_code":"USD","in_stock":true},{"title":"8.01mm \/ 1kg","offer_id":52409666601234,"sku":"LFL2024GANGZHU3969x1","price":66.38,"currency_code":"USD","in_stock":true},{"title":"8.02mm \/ 1kg","offer_id":52409666634002,"sku":"LFL2024GANGZHU3970x1","price":66.38,"currency_code":"USD","in_stock":true},{"title":"8.03mm \/ 1kg","offer_id":52409666666770,"sku":"LFL2024GANGZHU3971x1","price":66.38,"currency_code":"USD","in_stock":true},{"title":"8.04mm \/ 1kg","offer_id":52409666699538,"sku":"LFL2024GANGZHU3972x1","price":66.97,"currency_code":"USD","in_stock":true},{"title":"8.05mm \/ 1kg","offer_id":52409666732306,"sku":"LFL2024GANGZHU3973x1","price":67.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0884\/8936\/1682\/files\/Picture4of7_c2c4d032-9624-4700-ba62-2676e2894c58.jpg?v=1782142277","url":"https:\/\/homediyer.com\/products\/1kg-bicycle-45-steel-ball-bearing-g100-replacement-bearings-6-90mm-8-05mm","provider":"HomeDIYer","version":"1.0","type":"link"}