{"product_id":"4x-deep-groove-ball-bearings-mr52-mr149zz","title":"4x Deep Groove Ball Bearings MR52-MR149ZZ ID 2mm-9mm OD 5mm-14mm Thick 2.5mm-5mm","description":"\u003cdiv class=\"hdiy-desc\"\u003e\n\u003cdiv class=\"hdiy-overview\"\u003e\n\u003ch2\u003eDeep Groove Ball Bearings MR52–MR149ZZ — Miniature ZZ Shielded Bearings for Precision Applications\u003c\/h2\u003e\n\u003cp\u003eEngineers, hobbyists, and repair technicians working with compact rotating assemblies often struggle to source the exact miniature bearing size they need without ordering in bulk. This listing offers a pack of 4 deep groove ball bearings in 20 model options — from MR52ZZ (2×5×2.5mm) to MR149ZZ (9×14×5mm) — so you can get precisely what your build requires without overstocking.\u003c\/p\u003e\n\u003cp\u003eEach pack contains 4 identical deep groove ball bearings featuring a chrome steel (GCr15) raceway and double metal shields (ZZ designation). Inner diameters range from 2mm to 9mm (approx. 0.079″–0.354″), outer diameters from 5mm to 14mm (approx. 0.197″–0.551″), and widths from 2.5mm to 5mm (approx. 0.098″–0.197″). The ZZ shield keeps grease in and contaminants out without the added drag of rubber seals.\u003c\/p\u003e\n\u003cp\u003eThese miniature ball bearings are widely used in RC car wheel hubs and steering pivots, 3D printer extruder idlers and carriage rails, small DC motor end caps, drone arm pivots, and precision instrument spindles where low friction and compact dimensions are critical.\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 Fits any shaft and housing machined to standard MR-series dimensions. Verify your ID, OD, and width against the variant options before ordering.\u003c\/div\u003e\n\u003cdiv class=\"hdiy-features\"\u003e\n\u003ch2\u003e✅ Key Features of These Miniature Deep Groove Ball Bearings\u003c\/h2\u003e\n\u003cul class=\"hdiy-list\"\u003e\n\u003cli\u003e\n\u003cstrong\u003e20 Size Options in One Listing\u003c\/strong\u003e — MR52ZZ through MR149ZZ; select the exact model from the variant dropdown to match your shaft and bore dimensions.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDouble Metal Shield (ZZ)\u003c\/strong\u003e — Stamped steel shields on both sides retain factory grease and block particulate ingress, extending service life in dusty or debris-prone environments.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eChrome Steel Raceway (GCr15)\u003c\/strong\u003e — Through-hardened bearing steel delivers consistent load capacity and wear resistance across the full size range.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePack of 4\u003c\/strong\u003e — Four identical bearings per order; enough for a typical four-wheel RC drivetrain, dual-motor assembly, or spare-set stocking.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow-Profile Dimensions\u003c\/strong\u003e — ID from 2mm, OD up to 14mm; fits tight chassis pockets, slim motor housings, and compact 3D-printer carriages where space is at a premium.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDrop-In Replacement Geometry\u003c\/strong\u003e — Conforms to standard MR-series dimensional tolerances, making these direct replacements for worn OEM miniature bearings in most hobby and light-industrial equipment.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"hdiy-table-wrap\"\u003e\n\u003ch2\u003e📐 Technical Specifications — Miniature Deep Groove Ball Bearings\u003c\/h2\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eBearing Type\u003c\/th\u003e\n\u003ctd\u003eDeep Groove Ball Bearing\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eShield Type\u003c\/th\u003e\n\u003ctd\u003eDouble Metal Shield (ZZ)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eRaceway Material\u003c\/th\u003e\n\u003ctd\u003eChrome Steel (GCr15)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eInner Diameter (ID)\u003c\/th\u003e\n\u003ctd\u003e2mm – 9mm (0.079″ – 0.354″)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eOuter Diameter (OD)\u003c\/th\u003e\n\u003ctd\u003e5mm – 14mm (0.197″ – 0.551″)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eWidth (Thickness)\u003c\/th\u003e\n\u003ctd\u003e2.5mm – 5mm (0.098″ – 0.197″)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eAvailable Models\u003c\/th\u003e\n\u003ctd\u003eMR52ZZ, MR62ZZ, MR63ZZ, MR72ZZ, MR74ZZ, MR83ZZ, MR84ZZ, MR85ZZ, MR93ZZ, MR95ZZ, MR104ZZ, MR105ZZ, MR106ZZ, MR115ZZ, MR117ZZ, MR126ZZ, MR128ZZ, MR137ZZ, MR148ZZ, MR149ZZ\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eQuantity per Pack\u003c\/th\u003e\n\u003ctd\u003e4 pieces\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eLubrication\u003c\/th\u003e\n\u003ctd\u003eGrease-packed (factory pre-lubricated)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eOperating Temperature\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eDynamic Load Rating\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eDimensional Standard\u003c\/th\u003e\n\u003ctd\u003eMR-series (metric miniature)\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 choose the right bearing model for my application?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eMatch the model number to your shaft diameter (ID), housing bore (OD), and available axial space (width). For example, if your shaft is 4mm, your housing bore is 8mm, and you have 3mm of axial clearance, select MR84ZZ (4×8×3mm). Always measure your existing bearing or machined pocket before ordering.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eWhat does the \"ZZ\" designation mean?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eZZ indicates double metal shields — one stamped steel shield pressed into each side of the outer ring. The shields retain factory grease and block coarse contaminants. Unlike rubber seals (2RS), ZZ shields do not contact the inner ring, so friction and heat generation are slightly lower, making them well-suited for higher-speed, lower-load applications.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eAre these bearings suitable for outdoor or wet environments?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eMetal-shielded (ZZ) bearings are not fully waterproof. In wet or high-humidity environments, consider applying a compatible bearing grease after installation or upgrading to rubber-sealed (2RS) variants. For occasional light moisture exposure, the factory grease provides adequate short-term protection.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eCan I use these in my 3D printer (e.g., as idler bearings or carriage bearings)?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eYes. MR-series miniature bearings are a standard fit in many FDM printer designs. Common applications include extruder idler arms (often MR105ZZ or MR115ZZ), belt tensioner pulleys, and Z-axis lead screw supports. Confirm the ID, OD, and width against your printer's BOM or CAD files before ordering.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eWhat is the maximum speed these bearings can handle?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eMaximum permissible speed varies by model size and lubrication. Smaller-diameter bearings (e.g., MR52ZZ) typically support higher RPM than larger ones. As a conservative guideline, grease-lubricated MR-series bearings in this size range are rated for approximately 20,000–60,000 RPM depending on model. Contact us to confirm speed ratings for your specific model if your application is speed-critical.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eAre these a direct replacement for worn bearings in RC cars or drones?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eIn most cases, yes. MR-series bearings follow standardized metric miniature dimensions, so they are direct drop-in replacements for OEM bearings of the same model number. Verify the model number printed or stamped on your existing bearing before ordering to ensure an exact dimensional match.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eWhy buy a pack of 4 instead of individual bearings?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eMost hobby and light-industrial assemblies use bearings in pairs or sets of four — RC wheel hubs, dual-shaft motors, and 3D printer gantry systems are common examples. A pack of 4 covers a complete replacement set for these assemblies and provides spares for future maintenance without requiring a separate reorder.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"hdiy-cta\"\u003e\n\u003cp\u003e🛒 Select your Model IDxODxThick above, then add to cart.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"HomeDIYer","offers":[{"title":"MR52ZZ 2 x 5 x 2.5mm","offer_id":52409967673618,"sku":"ZBBPRTN021717x4","price":3.2,"currency_code":"USD","in_stock":true},{"title":"MR62ZZ 2 x 6 x 2.5mm","offer_id":52409967706386,"sku":"ZBBPRTN021718x4","price":3.2,"currency_code":"USD","in_stock":true},{"title":"MR63ZZ 3 x 6 x 2.5mm","offer_id":52409967739154,"sku":"ZBBPRTN021719x4","price":2.57,"currency_code":"USD","in_stock":true},{"title":"MR72ZZ 2 x 7 x 3mm","offer_id":52409967771922,"sku":"ZBBPRTN021720x4","price":3.2,"currency_code":"USD","in_stock":true},{"title":"MR74ZZ 4 x 7 x 2.5mm","offer_id":52409967804690,"sku":"ZBBPRTN021721x4","price":2.84,"currency_code":"USD","in_stock":true},{"title":"MR83ZZ 3 x 8 x 3mm","offer_id":52409967837458,"sku":"ZBBPRTN021722x4","price":2.57,"currency_code":"USD","in_stock":true},{"title":"MR84ZZ 4 x 8 x 3mm","offer_id":52409967870226,"sku":"ZBBPRTN021723x4","price":2.38,"currency_code":"USD","in_stock":true},{"title":"MR85ZZ 5 x 8 x 2.5mm","offer_id":52409967902994,"sku":"ZBBPRTN021724x4","price":2.84,"currency_code":"USD","in_stock":true},{"title":"MR93ZZ 3 x 9 x 4mm","offer_id":52409967935762,"sku":"ZBBPRTN021725x4","price":2.84,"currency_code":"USD","in_stock":true},{"title":"MR95ZZ 5 x 9 x 3mm","offer_id":52409967968530,"sku":"ZBBPRTN021726x4","price":2.57,"currency_code":"USD","in_stock":true},{"title":"MR104ZZ 4 x 10 x 4mm","offer_id":52409968001298,"sku":"ZBBPRTN021727x4","price":2.71,"currency_code":"USD","in_stock":true},{"title":"MR105ZZ 5 x 10 x 4mm","offer_id":52409968034066,"sku":"ZBBPRTN021728x4","price":2.57,"currency_code":"USD","in_stock":true},{"title":"MR106ZZ 6 x 10 x 3mm","offer_id":52409968066834,"sku":"ZBBPRTN021729x4","price":2.98,"currency_code":"USD","in_stock":true},{"title":"MR115ZZ 5 x 11 x 4mm","offer_id":52409968099602,"sku":"ZBBPRTN021730x4","price":2.52,"currency_code":"USD","in_stock":true},{"title":"MR117ZZ 7 x 11 x 3mm","offer_id":52409968132370,"sku":"ZBBPRTN021731x4","price":2.84,"currency_code":"USD","in_stock":true},{"title":"MR126ZZ 6 x 12 x 4mm","offer_id":52409968165138,"sku":"ZBBPRTN021732x4","price":2.38,"currency_code":"USD","in_stock":true},{"title":"MR128ZZ 8 x 12 x 3.5mm","offer_id":52409968197906,"sku":"ZBBPRTN021733x4","price":3.2,"currency_code":"USD","in_stock":true},{"title":"MR137ZZ 7 x 13 x 4mm","offer_id":52409968230674,"sku":"ZBBPRTN021734x4","price":2.84,"currency_code":"USD","in_stock":true},{"title":"MR148ZZ 8 x 14 x 4mm","offer_id":52409968263442,"sku":"ZBBPRTN021735x4","price":2.38,"currency_code":"USD","in_stock":true},{"title":"MR149ZZ 9 x 14 x 5mm","offer_id":52409968296210,"sku":"ZBBPRTN021736x4","price":2.98,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0884\/8936\/1682\/files\/Picture1of8_5688a962-135f-4d8f-bfe3-d65afc9d32b8.jpg?v=1782355684","url":"https:\/\/homediyer.com\/products\/4x-deep-groove-ball-bearings-mr52-mr149zz","provider":"HomeDIYer","version":"1.0","type":"link"}