{"product_id":"castair-replacement-motor-pulley-hub-shaft-3-95-od-2b-grooves","title":"Castair Replacement Motor Pulley Hub Shaft 3.95\" OD. 2B Grooves","description":"\u003ch2\u003eCast Air P2B395H — 3.95\" OD Dual-Groove B-Section Motor Pulley, Hub Mount\u003c\/h2\u003e\n\n\u003cp\u003eThe Cast Air P2B395H is a 3.95\" outside diameter motor pulley with two B-section belt grooves and a hub-mount bore configuration. It sits in the middle of the Cast Air small-to-mid dual-B-groove motor pulley range — larger than the 3.55\" P2B355H and slightly smaller than the 4.45\" P2B445H. The hub-mount design means the pulley body does not have a machined bore; instead, a separately ordered hub (LX, SD, or SK series, depending on shaft size) locks into the pulley center and clamps to the motor shaft. This gives the P2B395H flexibility across multiple shaft diameters without stocking a separate fixed-bore pulley for each combination.\u003c\/p\u003e\n\n\u003cp\u003eThe 3.95\" OD is close to the 4\" diameter common in fixed-bore pulleys, but is a distinct part with distinct drive ratio characteristics. If your compressor originally came with a 3.95\" motor pulley, replace it with the P2B395H. Do not substitute a 4.0\" pulley — the pump speed will be slightly higher than designed, which shifts the motor load curve and can cause nuisance tripping on compressors that are already running near motor capacity at operating pressure.\u003c\/p\u003e\n\n\u003ch3\u003ePulley Specifications\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e P2B395H\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOutside Diameter:\u003c\/strong\u003e 3.95\"\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBore Configuration:\u003c\/strong\u003e Hub mount (bore depends on hub selected)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNumber of Grooves:\u003c\/strong\u003e 2\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGroove Profile:\u003c\/strong\u003e B-section\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBelt compatibility:\u003c\/strong\u003e Two B-section V-belts (matched pair recommended)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Cast iron\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePrice:\u003c\/strong\u003e $38.50 (hub sold separately)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSelecting the Correct Hub\u003c\/h3\u003e\n\u003cp\u003eThe P2B395H is a hub-mount pulley. You must order a separate hub matched to your motor shaft size. Cast Air hub options:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLX58:\u003c\/strong\u003e 5\/8\" shaft\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLX78:\u003c\/strong\u003e 7\/8\" shaft\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLX100:\u003c\/strong\u003e 1\" shaft\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLX118:\u003c\/strong\u003e 1-1\/8\" shaft\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLX138:\u003c\/strong\u003e 1-3\/8\" shaft\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSD138:\u003c\/strong\u003e 1-3\/8\" shaft (SD taper-lock)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSD158:\u003c\/strong\u003e 1-5\/8\" shaft (SD taper-lock)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSK158:\u003c\/strong\u003e 1-5\/8\" shaft (SK taper-lock)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSK178:\u003c\/strong\u003e 1-7\/8\" shaft (SK taper-lock)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eMeasure your shaft diameter with calipers before ordering. Do not estimate. Common motor shaft sizes for Cast Air compressors in the size range this pulley serves include 7\/8\" (LX78) and 1\" (LX100). If you are replacing an existing hub-mount pulley, the old hub's markings will show the shaft size and hub series.\u003c\/p\u003e\n\n\u003ch3\u003eDrive Ratio at 3.95\" OD\u003c\/h3\u003e\n\u003cp\u003eThe motor pulley OD directly determines how fast the pump runs. To put the 3.95\" diameter in context:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eAt 1750 RPM motor speed with a 10\" pump pulley: pump runs at approximately 691 RPM\u003c\/li\u003e\n  \u003cli\u003eCompared to 3.55\" (P2B355H): the 3.95\" motor pulley increases pump speed by approximately 11%\u003c\/li\u003e\n  \u003cli\u003eCompared to 4.95\" (P2B495H): the 3.95\" motor pulley runs the pump approximately 20% slower\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eReplace like-for-like:\u003c\/strong\u003e Match the 3.95\" OD to maintain the original pump speed specification. Changing pulley diameter changes CFM output and motor load.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhen Hub-Mount Pulleys Are the Right Choice\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eYour shaft size is not available in a fixed-bore pulley:\u003c\/strong\u003e Fixed-bore pulleys in the Cast Air lineup are available at 5\/8\", 7\/8\", 1-1\/8\", and 1-3\/8\" for specific diameters. Hub mounts cover all shaft sizes.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThe original equipment used a hub mount:\u003c\/strong\u003e If you pull the old motor pulley and it has a hub locking ring or taper bushing, replace it with the same hub-mount configuration.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eYou want to separate the pulley and hub replacement cycles:\u003c\/strong\u003e Hubs typically wear slower than pulleys (groove wear). A hub-mount system lets you replace only the worn component.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eDual-Belt Drive Maintenance Notes\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAlways replace belts in matched pairs:\u003c\/strong\u003e Installing one new belt alongside an old belt means the stiffer old belt carries more load, wearing faster and putting uneven side loads on the shaft bearings.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCheck groove alignment:\u003c\/strong\u003e The motor pulley grooves and pump pulley grooves must be in the same plane. Misaligned grooves cause the belts to run at an angle, generating heat and wearing both the belt and groove edges prematurely.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eInspect the pump pulley at the same time:\u003c\/strong\u003e When replacing the motor pulley, check the pump pulley grooves for wear and verify the pump shaft bearings are free of play.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eFull 2B Hub Motor Pulley Comparison\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eP2B355H:\u003c\/strong\u003e 3.55\" OD, hub mount — $38.50\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eP2B395H (this pulley):\u003c\/strong\u003e 3.95\" OD, hub mount — $38.50\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eP2B445H:\u003c\/strong\u003e 4.45\" OD, hub mount\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eP2B495H:\u003c\/strong\u003e 4.95\" OD, hub mount — $66.41\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eP2B335-7\/8:\u003c\/strong\u003e 3.35\" OD, 7\/8\" fixed bore — $38.50\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e P2B395H\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOutside Diameter:\u003c\/strong\u003e 3.95\"\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBore:\u003c\/strong\u003e Hub mount (hub ordered separately)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNumber of Grooves:\u003c\/strong\u003e 2\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGroove Profile:\u003c\/strong\u003e B-section\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Cast iron\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePrice:\u003c\/strong\u003e $38.50 (hub not included)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhy Buy From Air Compressor Factory Direct?\u003c\/h3\u003e\n\u003cp\u003eHub-mount pulleys require you to get two parts right. We stock both the P2B395H and the full LX, SD, and SK hub range. Call us with your shaft diameter and we will build the complete parts list for you — pulley, hub, and belts if needed — so you can do the job with one order and one shipment.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFree shipping\u003c\/strong\u003e on qualifying orders\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFree tech support:\u003c\/strong\u003e Call 866-217-0063 — confirm your shaft size and we will identify the right hub\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFull manufacturer warranty\u003c\/strong\u003e on all Cast Air parts\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHonest guidance:\u003c\/strong\u003e We will verify you have both the pulley and the matching hub before you complete the order\u003c\/li\u003e\n\u003c\/ul\u003e\n\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":53342573330645,"sku":"P2B395H","price":71.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0622\/8466\/0949\/files\/MOTOR-PULLEYS-300x248_f92a0503-a518-4616-aab3-38e8efae669c.jpg?v=1772652766","url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-replacement-motor-pulley-hub-shaft-3-95-od-2b-grooves","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}