{"product_id":"12-pitch-08b-steel-idler-sprocket-ball-bearing","title":"1\/2\" Pitch Steel Idler Sprocket with Ball Bearing for 08B Roller Chain Tensioner","description":"\u003cdiv class=\"hdiy-desc\"\u003e\n\n  \u003cdiv class=\"hdiy-overview\"\u003e\n    \u003ch2\u003e1\/2\" Pitch 08B Idler Sprocket with Ball Bearing — Reliable Chain Tensioning for Roller Drive Systems\u003c\/h2\u003e\n    \u003cp\u003eWhen a roller chain drive runs slack, vibration increases, efficiency drops, and premature wear follows. Engineers, fabricators, and DIY machine builders who need a dependable tensioning solution turn to a dedicated idler sprocket — one that holds chain tension without adding load to the drive shaft. This 1\/2\" pitch steel idler sprocket with ball bearing is engineered specifically for 08B roller chain tensioner applications, giving you a stable, low-friction contact point that keeps your chain taut under varying loads.\u003c\/p\u003e\n    \u003cp\u003eEach sprocket is machined from carbon steel and finished to resist surface wear. Tooth counts range from 13 to 19 teeth, with bore sizes spanning 10 mm (0.39 in) to 20 mm (0.79 in). Single-bearing variants suit lighter-duty or space-constrained installations; double-bearing variants provide added radial support for higher-load or higher-speed applications. Chain pitch is 1\/2\" (12.7 mm), conforming to the 08B ISO standard.\u003c\/p\u003e\n    \u003cp\u003eTypical use cases include conveyor tensioner assemblies, agricultural machinery chain drives, go-kart and mini-bike drivetrain tensioners, and custom power-transmission rigs where an 08B roller chain idler sprocket with adjustable bore is required. The available bore range makes this sprocket compatible with a wide variety of shaft diameters without custom machining.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-compat\"\u003e\n    \u003cspan class=\"hdiy-compat-icon\"\u003e🔗\u003c\/span\u003e\n    \u003cstrong\u003eChain Compatibility:\u003c\/strong\u003e Designed for \u003cstrong\u003e08B ISO roller chain\u003c\/strong\u003e — 1\/2\" (12.7 mm) pitch, 5\/16\" (7.94 mm) roller diameter. Verify your chain standard before ordering.\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-features\"\u003e\n    \u003ch2\u003e✅ Key Features of These 08B Idler Sprockets with Ball Bearing\u003c\/h2\u003e\n    \u003cul class=\"hdiy-list\"\u003e\n      \u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e⚙️\u003c\/span\u003e\u003cstrong\u003e08B ISO Standard Pitch\u003c\/strong\u003e — 1\/2\" (12.7 mm) pitch matches 08B roller chain exactly, ensuring full tooth engagement and smooth tensioner operation without chain skipping.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🎯\u003c\/span\u003e\u003cstrong\u003eMultiple Tooth Counts\u003c\/strong\u003e — Available in 13, 15, 17, and 19 teeth so you can match the wrap angle and tensioner geometry your specific drive layout requires.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🔩\u003c\/span\u003e\u003cstrong\u003eSingle or Double Bearing Options\u003c\/strong\u003e — Single-bearing models keep weight and cost down for lighter applications; double-bearing models add radial rigidity for higher-load or higher-speed chain tensioner setups.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e📐\u003c\/span\u003e\u003cstrong\u003eWide Bore Range (10–20 mm)\u003c\/strong\u003e — Five bore sizes (10, 12, 15, 17, 20 mm) let you mount directly onto your existing shaft without sleeve adapters or custom boring in most standard installations.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🛡️\u003c\/span\u003e\u003cstrong\u003eCarbon Steel Construction\u003c\/strong\u003e — Machined from carbon steel for the tooth hardness and structural integrity needed to withstand continuous chain contact and tensioner side-loading.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🔄\u003c\/span\u003e\u003cstrong\u003eLow-Friction Ball Bearing Core\u003c\/strong\u003e — The integrated ball bearing allows the sprocket to spin freely on a fixed idler shaft, reducing friction heat and extending both chain and sprocket service life.\u003c\/li\u003e\n    \u003c\/ul\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-table-wrap\"\u003e\n    \u003ch2\u003e📐 Technical Specifications — 08B Idler Sprocket\u003c\/h2\u003e\n    \u003ctable\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n\u003cth\u003eChain Standard\u003c\/th\u003e\n\u003ctd\u003e08B ISO (BS)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eChain Pitch\u003c\/th\u003e\n\u003ctd\u003e1\/2\" (12.7 mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eRoller Diameter (chain)\u003c\/th\u003e\n\u003ctd\u003e5\/16\" (7.94 mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eNumber of Teeth\u003c\/th\u003e\n\u003ctd\u003e13 \/ 15 \/ 17 \/ 19 (see variant options)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eBearing Type\u003c\/th\u003e\n\u003ctd\u003eSingle Ball Bearing \/ Double Ball Bearings (see variant options)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eBore Size\u003c\/th\u003e\n\u003ctd\u003e10 mm \/ 12 mm \/ 15 mm \/ 17 mm \/ 20 mm (see variant options)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eMaterial\u003c\/th\u003e\n\u003ctd\u003eCarbon Steel\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eOuter Diameter\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eHub Width\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eFinish\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eQuantity per Order\u003c\/th\u003e\n\u003ctd\u003e1 pc\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eWeight\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\n  \u003cdiv class=\"hdiy-faq\"\u003e\n    \u003ch2\u003e❓ Frequently Asked Questions\u003c\/h2\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWhich chain standard does this idler sprocket fit?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eThis sprocket is designed for \u003cstrong\u003e08B ISO (British Standard) roller chain\u003c\/strong\u003e with a 1\/2\" (12.7 mm) pitch and a 5\/16\" (7.94 mm) roller diameter. It is not interchangeable with ANSI #40 chain, which shares the same pitch but has a different roller diameter. Always confirm your chain's ISO or ANSI designation before ordering.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eHow do I choose between single bearing and double bearing?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eSingle-bearing idler sprockets are suited for lighter loads, lower speeds, and space-constrained installations where minimizing weight matters. Double-bearing variants provide greater radial support, making them the better choice for higher chain tension, higher RPM, or applications where the idler shaft experiences significant side loading. If in doubt, the double-bearing option offers a wider safety margin.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eHow do I select the correct bore size?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eMeasure your idler shaft diameter with a caliper and select the matching bore: 10 mm, 12 mm, 15 mm, 17 mm, or 20 mm. The bore should be a close sliding fit on the shaft — not loose. If your shaft diameter falls between available sizes, choose the next smaller bore and have it bored out by a machine shop, or use a shaft sleeve to step up to the next available size.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eHow many teeth should I choose for my tensioner?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eFor idler\/tensioner applications, tooth count affects the wrap angle and the smoothness of chain engagement. A 13-tooth sprocket is compact and suits tight-space tensioners; 15–17 teeth offer a balance of size and smooth engagement; 19 teeth provide the largest contact arc and the gentlest chain articulation angle. Match the tooth count to the available space in your tensioner bracket and the minimum wrap angle your drive requires.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eIs this sprocket corrosion-resistant for outdoor or wet environments?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eThe sprocket is machined from carbon steel, which provides good mechanical strength but has limited inherent corrosion resistance. For outdoor, humid, or washdown environments, apply a chain lubricant or anti-rust coating regularly. If your application demands higher corrosion resistance, consider stainless steel alternatives or apply a protective surface treatment after installation.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eCan I use this sprocket as a drive sprocket instead of an idler?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eThis sprocket is designed for idler\/tensioner use — it spins freely on a fixed shaft via its ball bearing. It is not intended to be keyed or locked to a rotating drive shaft for power transmission. Using it as a drive sprocket would bypass the bearing and could damage the bore or bearing race. For driven applications, use a standard 08B sprocket with a keyway and set-screw hub.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWhat lubrication does the ball bearing require?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eThe integrated ball bearing is typically pre-greased and sealed for maintenance-free operation under normal conditions. For high-temperature or high-load environments, inspect the bearing periodically and re-grease if the bearing type allows access. Additionally, keep the chain itself lubricated with a suitable roller chain oil to reduce wear on the sprocket teeth and extend service intervals.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-cta\"\u003e\n    🛒 Select your tooth count, bearing type, and bore size above, then add to cart.\n  \u003c\/div\u003e\n\n\u003c\/div\u003e","brand":"HomeDIYer","offers":[{"title":"13 Tooth【Single Bearing】 \/ 10mm \/ 1 pcs","offer_id":52423342227730,"sku":"PENGDZ01267x1","price":19.38,"currency_code":"USD","in_stock":true},{"title":"13 Tooth【Single Bearing】 \/ 12mm \/ 1 pcs","offer_id":52423342260498,"sku":"PENGDZ01268x1","price":19.38,"currency_code":"USD","in_stock":true},{"title":"15 Tooth【Single Bearing】 \/ 10mm \/ 1 pcs","offer_id":52423342293266,"sku":"PENGDZ01269x1","price":24.87,"currency_code":"USD","in_stock":true},{"title":"15 Tooth【Single Bearing】 \/ 12mm \/ 1 pcs","offer_id":52423342326034,"sku":"PENGDZ01270x1","price":24.87,"currency_code":"USD","in_stock":true},{"title":"15 Tooth【Single Bearing】 \/ 15mm \/ 1 pcs","offer_id":52423342358802,"sku":"PENGDZ01271x1","price":24.87,"currency_code":"USD","in_stock":true},{"title":"15 Tooth【Single Bearing】 \/ 17mm \/ 1 pcs","offer_id":52423342391570,"sku":"PENGDZ01272x1","price":24.87,"currency_code":"USD","in_stock":true},{"title":"17 Tooth【Single Bearing】 \/ 15mm \/ 1 pcs","offer_id":52423342424338,"sku":"PENGDZ01273x1","price":32.49,"currency_code":"USD","in_stock":true},{"title":"17 Tooth【Single Bearing】 \/ 17mm \/ 1 pcs","offer_id":52423342457106,"sku":"PENGDZ01274x1","price":32.49,"currency_code":"USD","in_stock":true},{"title":"17 Tooth【Single Bearing】 \/ 20mm \/ 1 pcs","offer_id":52423342489874,"sku":"PENGDZ01275x1","price":32.49,"currency_code":"USD","in_stock":true},{"title":"19 Tooth【Single Bearing】 \/ 15mm \/ 1 pcs","offer_id":52423342522642,"sku":"PENGDZ01276x1","price":41.47,"currency_code":"USD","in_stock":true},{"title":"19 Tooth【Single Bearing】 \/ 17mm \/ 1 pcs","offer_id":52423342555410,"sku":"PENGDZ01277x1","price":41.47,"currency_code":"USD","in_stock":true},{"title":"19 Tooth【Single Bearing】 \/ 20mm \/ 1 pcs","offer_id":52423342588178,"sku":"PENGDZ01278x1","price":41.47,"currency_code":"USD","in_stock":true},{"title":"13 Tooth【Double Bearings】 \/ 10mm \/ 1 pcs","offer_id":52423342620946,"sku":"PENGDZ01279x1","price":23.65,"currency_code":"USD","in_stock":true},{"title":"13 Tooth【Double Bearings】 \/ 12mm \/ 1 pcs","offer_id":52423342653714,"sku":"PENGDZ01280x1","price":23.38,"currency_code":"USD","in_stock":true},{"title":"15 Tooth【Double Bearings】 \/ 10mm \/ 1 pcs","offer_id":52423342686482,"sku":"PENGDZ01281x1","price":34.48,"currency_code":"USD","in_stock":true},{"title":"15 Tooth【Double Bearings】 \/ 12mm \/ 1 pcs","offer_id":52423342719250,"sku":"PENGDZ01282x1","price":34.2,"currency_code":"USD","in_stock":true},{"title":"15 Tooth【Double Bearings】 \/ 15mm \/ 1 pcs","offer_id":52423342752018,"sku":"PENGDZ01283x1","price":33.44,"currency_code":"USD","in_stock":true},{"title":"15 Tooth【Double Bearings】 \/ 17mm \/ 1 pcs","offer_id":52423342784786,"sku":"PENGDZ01284x1","price":32.84,"currency_code":"USD","in_stock":true},{"title":"17 Tooth【Double Bearings】 \/ 15mm \/ 1 pcs","offer_id":52423342817554,"sku":"PENGDZ01285x1","price":45.14,"currency_code":"USD","in_stock":true},{"title":"17 Tooth【Double Bearings】 \/ 17mm \/ 1 pcs","offer_id":52423342850322,"sku":"PENGDZ01286x1","price":44.59,"currency_code":"USD","in_stock":true},{"title":"17 Tooth【Double Bearings】 \/ 20mm \/ 1 pcs","offer_id":52423342883090,"sku":"PENGDZ01287x1","price":43.51,"currency_code":"USD","in_stock":true},{"title":"19 Tooth【Double Bearings】 \/ 15mm \/ 1 pcs","offer_id":52423342915858,"sku":"PENGDZ01288x1","price":60.1,"currency_code":"USD","in_stock":true},{"title":"19 Tooth【Double Bearings】 \/ 17mm \/ 1 pcs","offer_id":52423342948626,"sku":"PENGDZ01289x1","price":59.09,"currency_code":"USD","in_stock":true},{"title":"19 Tooth【Double Bearings】 \/ 20mm \/ 1 pcs","offer_id":52423342981394,"sku":"PENGDZ01290x1","price":58.06,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0884\/8936\/1682\/files\/Picture9of18_4035c2ec-5677-429b-bec6-ef8b739e3da7.jpg?v=1782804384","url":"https:\/\/homediyer.com\/products\/12-pitch-08b-steel-idler-sprocket-ball-bearing","provider":"HomeDIYer","version":"1.0","type":"link"}