{"product_id":"castair-2-groove-motor-pulley-p2b975sk-p2b975sk","title":"Castair 2-Groove Motor Pulley P2B975SK - P2B975SK","description":"\u003cp\u003eThe Castair P2B975SK is a 2-groove (2B) motor pulley with an SK-style taper-lock hub and 9.75\" outer diameter. The SK designation means this pulley uses a standard SK bushing (sold separately) rather than a fixed bore — which lets you adapt it to a range of motor shaft diameters by selecting the correct SK bushing for your shaft size. This is the largest 2-groove motor pulley in the Cast Air SK-hub lineup and is used on higher-HP belt-drive compressors where maximum drive ratio from the motor side is required.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eNote: Cast Air did not provide a dedicated manufacturer product page for this pulley.\u003c\/strong\u003e Specifications are drawn from the product listing and standard SK-hub 2B pulley engineering conventions. Contact us before ordering to confirm bushing compatibility and fitment for your specific compressor.\u003c\/p\u003e\n\n\u003ch2\u003eUnderstanding SK Taper-Lock Hubs\u003c\/h2\u003e\n\u003cp\u003eAn SK hub is a taper-lock bushing system. The pulley itself has a tapered bore that mates with a matching SK bushing. The bushing is bored to your specific shaft diameter (common sizes: 1-1\/8\", 1-3\/8\", 1-5\/8\", etc.) and has a keyway and set screws. You install the bushing on the shaft, slide the pulley onto the bushing, and the taper draws tight as you torque the mounting screws — creating a secure, concentric fit. SK-hub pulleys can be reused with different motors by swapping bushings, making them the practical choice for industrial installations where motors get replaced periodically.\u003c\/p\u003e\n\n\u003ch3\u003ePulley Specification Details\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eGroove Profile:\u003c\/strong\u003e 2B (two B-section V-belt grooves)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHub Type:\u003c\/strong\u003e SK taper-lock (bushing required, sold separately)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOuter Diameter (OD):\u003c\/strong\u003e 9.75\"\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e Motor-side pulley for belt-drive air compressors\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Cast Air belt-drive compressors using SK-hub motor pulleys and B-section belts\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e P2B975SK\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhat the 9.75\" OD Means for Pump Speed\u003c\/h2\u003e\n\u003cp\u003eThis is the largest 2B motor pulley in the Cast Air SK lineup. A 9.75\" motor pulley paired with a 14\" pump flywheel produces a drive ratio of approximately 1.44:1 — meaning a 1,750 RPM motor drives the pump at about 1,214 RPM. For most single-stage pumps this is above the normal operating range, so this pulley is typically found on two-stage or heavy-duty Cast Air pump designs that are rated for higher RPM, or paired with a motor and flywheel combination specifically engineered for this drive ratio. Do not use this as an upgrade on a compressor not designed for it.\u003c\/p\u003e\n\n\u003ch3\u003eWhen to Choose SK Hub vs. Fixed Bore\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSK hub (this pulley):\u003c\/strong\u003e Requires a separate SK bushing sized to your motor shaft. Allows the same pulley to work with different shaft diameters by swapping the bushing. Best for commercial\/industrial applications where motor replacement is anticipated.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFixed bore:\u003c\/strong\u003e Machined to one specific shaft diameter. Simpler installation, lower cost, correct for direct replacement when motor shaft is unchanged.\u003c\/li\u003e\n\u003cli\u003eIf your original motor pulley was SK-hub, replace with SK-hub and the matching bushing. Do not substitute a fixed-bore pulley — the hub geometry is incompatible.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhen Does a Shop Need the P2B975SK?\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eOriginal 9.75\" SK-hub motor pulley is worn, cracked, or damaged\u003c\/li\u003e\n\u003cli\u003eRebuilding a heavy-duty Cast Air compressor that factory-shipped with the P2B975SK\u003c\/li\u003e\n\u003cli\u003eMotor replacement on a compressor where the SK bushing can be reused on the new motor shaft\u003c\/li\u003e\n\u003cli\u003eInstalling a different shaft-size motor where a new SK bushing is needed but the pulley OD remains the same\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e P2B975SK\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer:\u003c\/strong\u003e Cast Air (Castair)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGroove Type:\u003c\/strong\u003e 2B (two B-section V-belt grooves)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHub Type:\u003c\/strong\u003e SK taper-lock (bushing sold separately)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOuter Diameter:\u003c\/strong\u003e 9.75\"\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBelt Section:\u003c\/strong\u003e B-section (two matched belts)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrice:\u003c\/strong\u003e Contact for current pricing\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Data:\u003c\/strong\u003e Product page not available — specifications from product listing data\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhat Is Included\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e1x Castair P2B975SK motor pulley (SK hub)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eSK bushing and B-section matched belts are not included. Specify your motor shaft diameter when ordering to get the correct SK bushing for your application.\u003c\/p\u003e\n\n\u003ch2\u003eWhy Buy From Air Compressor Factory Direct?\u003c\/h2\u003e\n\u003cp\u003eSK-hub pulley systems require matching components — the right bushing for your shaft size, the right belt length for your drive center distance. We have been selling Cast Air parts since 2016 and can help you identify all the components you need in one order. Free shipping, free tech support, and full manufacturer warranty on every Cast Air part.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCast Air specialist\u003c\/strong\u003e since 2016\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFree shipping\u003c\/strong\u003e on all orders\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFree tech support\u003c\/strong\u003e — we help you select the correct SK bushing and belt\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eFull manufacturer warranty\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eComplete system sourcing\u003c\/strong\u003e — pulley, bushing, and belts all from one order\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eCall 866-217-0063 for quick answers and help!\u003c\/strong\u003e\u003c\/p\u003e","brand":"Cast Air","offers":[{"title":"Default Title","offer_id":53342573920469,"sku":"P2B975SK","price":259.86,"currency_code":"USD","in_stock":true}],"url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-2-groove-motor-pulley-p2b975sk-p2b975sk","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}