{"product_id":"pu-round-belt-polyurethane-closed-loop-drive-belt","title":"PU Round Belt Polyurethane Closed Loop Drive Belt — 4, 5, 6, 8, 10mm Diameter","description":"\u003cp\u003e \u003c\/p\u003e\n\u003cdiv class=\"hdiy-desc\"\u003e\n\u003c!-- ① OVERVIEW --\u003e\n\u003cdiv class=\"hdiy-overview\"\u003e\n\u003ch2\u003ePU Round Belt — Reliable Closed-Loop Polyurethane Drive Belting for Machines of All Sizes\u003c\/h2\u003e\n\u003cp\u003eWhen a worn or snapped drive belt brings your lathe, sewing machine, or conveyor to a halt, finding an exact replacement fast is everything. Hobbyists, repair technicians, and small-shop machinists all face the same frustration: generic belts that stretch, slip, or simply don't come in the right size. These seamless polyurethane round drive belts are stocked in five diameters and dozens of perimeter lengths so you can get the right fit without custom fabrication.\u003c\/p\u003e\n\u003cp\u003eEach belt is a single-piece closed-loop construction — no joints, no glued seams — made from solid polyurethane (PU). Available diameters are 4mm, 5mm, 6mm, 8mm, and 10mm. Perimeter options range from 150mm (≈5.9\") up to 1035mm (≈40.7\"), covering a wide range of pulley center distances. Each listing is sold as 1 piece; select your exact diameter and perimeter combination from the variant options above.\u003c\/p\u003e\n\u003cp\u003eTypical applications include replacement drive belts for sewing machines and sergers, spindle drive belts on wood lathes and drill presses, light conveyor and packaging line drives, and small-motor power transmission in DIY and maker projects where a quiet, smooth polyurethane closed-loop round belt is required.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c!-- ② COMPATIBILITY BAR --\u003e\n\u003cdiv class=\"hdiy-compat\"\u003e\n\u003cspan class=\"hdiy-compat-icon\"\u003eℹ️\u003c\/span\u003e \u003cstrong\u003eCompatibility Note:\u003c\/strong\u003e These belts fit standard round-groove (O-groove \/ U-groove) pulleys. Match the belt diameter to your pulley groove radius. Verify your required perimeter before ordering — see the FAQ below for the measurement formula.\u003c\/div\u003e\n\u003c!-- ③ KEY FEATURES --\u003e\n\u003ch2\u003e✅ Key Features of These Polyurethane Closed-Loop Round Drive Belts\u003c\/h2\u003e\n\u003cul class=\"hdiy-features\"\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🔗\u003c\/span\u003e \u003cspan\u003e\u003cstrong\u003eSeamless Closed-Loop Construction\u003c\/strong\u003e — No joints, welds, or adhesive seams means no weak points. The belt runs smoothly through the full rotation without the vibration or noise that spliced belts can introduce.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e📐\u003c\/span\u003e \u003cspan\u003e\u003cstrong\u003eWide Size Selection\u003c\/strong\u003e — Five diameters (4, 5, 6, 8, 10mm) paired with perimeter options from 150mm to 1035mm let you find an exact match for most light-to-medium drive applications without custom cutting or splicing.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e💪\u003c\/span\u003e \u003cspan\u003e\u003cstrong\u003eSolid Polyurethane Material\u003c\/strong\u003e — PU offers higher abrasion resistance and tensile strength than standard rubber round belts, and it resists elongation under sustained load — helping maintain consistent belt tension over time.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🌊\u003c\/span\u003e \u003cspan\u003e\u003cstrong\u003eOil and Moisture Resistant\u003c\/strong\u003e — Polyurethane is naturally resistant to oils, water, and many common workshop chemicals, making these belts suitable for lightly oiled machinery environments where rubber belts tend to degrade faster.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🔇\u003c\/span\u003e \u003cspan\u003e\u003cstrong\u003eSmooth, Quiet Operation\u003c\/strong\u003e — The round cross-section and solid PU construction allow the belt to flex evenly around pulleys, reducing drive noise — a noticeable advantage in sewing machines, small lathes, and precision instruments.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🔄\u003c\/span\u003e \u003cspan\u003e\u003cstrong\u003eDirect Replacement Fit\u003c\/strong\u003e — Designed as a drop-in replacement for OEM round drive belts on sewing machines, woodworking equipment, and light industrial conveyors. No tools required for installation on most open-frame pulley systems.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- ④ TECHNICAL SPECIFICATIONS --\u003e\n\u003ch2\u003e📐 Technical Specifications — Polyurethane Round Drive Belt\u003c\/h2\u003e\n\u003cdiv class=\"hdiy-table-wrap\"\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eMaterial\u003c\/th\u003e\n\u003ctd\u003eSolid Polyurethane (PU)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eBelt Type\u003c\/th\u003e\n\u003ctd\u003eClosed-loop (seamless, no joint)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eCross-Section\u003c\/th\u003e\n\u003ctd\u003eRound (circular)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eAvailable Diameters\u003c\/th\u003e\n\u003ctd\u003e4mm (≈5\/32\"), 5mm (≈3\/16\"), 6mm (≈1\/4\"), 8mm (≈5\/16\"), 10mm (≈3\/8\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eAvailable Perimeters\u003c\/th\u003e\n\u003ctd\u003e150mm (≈5.9\") – 1035mm (≈40.7\"); see variant options for full list\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eColor\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003ePulley Compatibility\u003c\/th\u003e\n\u003ctd\u003eStandard round-groove (O-groove \/ U-groove) pulleys\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eTypical Load Rating\u003c\/th\u003e\n\u003ctd\u003eLight to medium duty — contact us to confirm for specific applications\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eTemperature Range\u003c\/th\u003e\n\u003ctd\u003eTypically suitable for –20°C to +80°C (–4°F to +176°F); confirm for high-heat environments\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eQuantity per Order\u003c\/th\u003e\n\u003ctd\u003e1 piece\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eCountry of Origin\u003c\/th\u003e\n\u003ctd\u003eSee variant options \/ Contact us to confirm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"hdiy-note\"\u003e\n\u003cspan class=\"hdiy-note-icon\"\u003e⚠️\u003c\/span\u003e \u003cstrong\u003eSize Tip:\u003c\/strong\u003e The perimeter listed is the full loop circumference. Measure your belt path around both pulleys before ordering. If you are between sizes, generally size up and allow for tension adjustment.\u003c\/div\u003e\n\u003c!-- ⑤ FAQ --\u003e\n\u003ch2\u003e❓ Frequently Asked Questions\u003c\/h2\u003e\n\u003cdiv class=\"hdiy-faq\"\u003e\n\u003cdetails\u003e\n\u003csummary\u003eHow do I choose the right perimeter (loop length) for my machine?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eMeasure the center-to-center distance between your two pulleys, then use this formula: \u003cstrong\u003ePerimeter ≈ 2 × center distance + π × pulley diameter\u003c\/strong\u003e. For example, a 100mm center distance with 20mm-diameter pulleys typically requires a belt perimeter of around 263mm (≈10.4\"). Always add a small tension allowance — generally 1–3% — when selecting your size. If you are between two listed perimeters, choose the larger one and adjust tension accordingly.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eWhat diameter belt should I choose — 4mm, 5mm, 6mm, 8mm, or 10mm?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eSmaller diameters (4–5mm) are generally suited for light-duty applications such as small motors, sewing machines, and precision instruments. Mid-range diameters (6–8mm) work well for woodworking equipment, conveyors, and general machinery. The 10mm diameter is typically used for heavier-duty drives requiring greater torque transmission. Check your machine's service manual or the OEM belt part number to confirm the correct diameter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eHow strong is a polyurethane round belt compared to rubber?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003ePolyurethane round belts generally offer higher tensile strength and abrasion resistance than standard rubber belts of the same diameter. PU material typically maintains its shape under repeated flexing and resists elongation better over time, making it a reliable choice for continuous-duty applications. In most cases, a PU belt will outlast a comparable rubber belt in workshop environments where oils and abrasives are present.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eCan these belts be used outdoors or in wet environments?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003ePolyurethane is inherently resistant to moisture, oils, and many common chemicals, making these belts suitable for use in damp or lightly oiled environments. However, prolonged UV exposure or immersion in harsh solvents may degrade the material over time. For outdoor installations, shielding the belt from direct sunlight is generally recommended to extend service life.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eAre these closed-loop belts compatible with standard round-groove pulleys?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eYes. These seamless closed-loop round belts are designed to run in standard round-groove (U-groove or O-groove) pulleys. Ensure the pulley groove radius matches the belt diameter — for example, a 6mm belt typically requires a pulley groove with a radius of approximately 3mm. Mismatched groove profiles can cause the belt to ride high or low in the groove, leading to premature wear or slippage.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eWhat machines commonly use this type of round drive belt?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003ePolyurethane closed-loop round belts are commonly used in sewing machines and sergers, wood lathes, drill presses, small conveyors, packaging equipment, and various light-to-medium industrial drives. They are also popular in DIY and maker projects where a smooth, quiet belt drive is needed. If you are unsure whether this belt suits your specific machine, feel free to contact us with your model number.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eIs the perimeter measurement the inner circumference or the outer circumference?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eThe perimeter listed in our variant options refers to the overall loop circumference of the belt, typically measured at the neutral axis (approximately the center of the belt cross-section). When matching to your machine, compare this figure to the required belt path length around your pulleys. In most cases the difference between inner and outer circumference on these small-diameter belts is minimal, but if precision is critical, contact us to confirm.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003c\/div\u003e\n\u003c!-- ⑥ CTA BAR --\u003e\n\u003cdiv class=\"hdiy-cta\"\u003e🛒 Select your diameter and perimeter above, then add to cart — ships from our US warehouse.\u003c\/div\u003e\n\u003c\/div\u003e","brand":"HomeDIYer","offers":[{"title":"6mm \/ 215mm \/ 1Pcs","offer_id":52377930563858,"sku":"FXLGB812-0","price":3.98,"currency_code":"USD","in_stock":true},{"title":"6mm \/ 242mm \/ 1Pcs","offer_id":52377930596626,"sku":"FXLGB812-1","price":3.98,"currency_code":"USD","in_stock":true},{"title":"6mm \/ 280mm \/ 1Pcs","offer_id":52377930629394,"sku":"FXLGB812-2","price":3.98,"currency_code":"USD","in_stock":true},{"title":"6mm \/ 320mm \/ 1Pcs","offer_id":52377930662162,"sku":"FXLGB812-3","price":4.56,"currency_code":"USD","in_stock":true},{"title":"6mm \/ 358mm 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