{"product_id":"castair-replacement-motor-pulley-hub-shaft-4-55-od-2b-grooves","title":"Castair Replacement Motor Pulley Hub Shaft, 4.55\" OD. 2B Grooves","description":"\u003ch2\u003eCast Air P2B455H — 4.55\" OD Dual-Groove B-Section Motor Pulley, Hub Mount\u003c\/h2\u003e\n\n\u003cp\u003eThe Cast Air P2B455H is a 4.55\" outside diameter motor pulley with two B-section belt grooves and a hub-mount bore configuration. It requires a separately ordered hub (LX, SD, or SK series) matched to your motor shaft diameter. This pulley sits in the mid-range of the Cast Air 2B hub motor pulley lineup — larger than the 3.95\" P2B395H and smaller than the 4.95\" P2B495H — producing moderate-to-high pump speeds on 1750 RPM four-pole motors.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eImportant note on part number verification:\u003c\/strong\u003e The P2B455H (4.55\" OD) is listed in our database at $64.49, but the closest current listing on the Cast Air website is the P2B445H at 4.45\" OD. There is a 0.1\" difference in outside diameter between these two part numbers, which produces a small but real difference in pump RPM. Before placing your order, please call us at 866-217-0063 so we can verify the exact part you need — whether that is the 4.55\" unit, the 4.45\" unit, or a different diameter entirely. We would rather spend two minutes confirming the right part than have you receive the wrong one.\u003c\/p\u003e\n\n\u003ch3\u003ePulley Specifications (As Listed)\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e P2B455H\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOutside Diameter:\u003c\/strong\u003e 4.55\"\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)\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 $64.49 (hub sold separately)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eP2B455H vs. P2B445H — What the Difference Means\u003c\/h3\u003e\n\u003cp\u003eA 0.1\" difference in pulley OD may seem trivial, but it produces a measurable difference in pump speed:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eP2B455H (4.55\" OD):\u003c\/strong\u003e At 1750 RPM motor speed with a 10\" pump pulley → pump runs at approximately 796 RPM\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eP2B445H (4.45\" OD):\u003c\/strong\u003e At 1750 RPM motor speed with a 10\" pump pulley → pump runs at approximately 779 RPM\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDifference:\u003c\/strong\u003e About 17 RPM at the pump, or roughly 2.2% more pump speed with the 4.55\" pulley\u003c\/li\u003e\n  \u003cli\u003eOn most applications this is within acceptable tolerance. On a compressor already running near motor capacity, the additional load from the higher RPM could cause nuisance tripping.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIf you are replacing a failed pulley:\u003c\/strong\u003e Check the OD of the original before ordering. If it measures 4.45\", order the P2B445H. If it measures 4.55\", the P2B455H is correct — but call us to confirm availability.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSelecting the Correct Hub\u003c\/h3\u003e\n\u003cp\u003eHub-mount pulleys require a separately ordered hub. Cast Air hubs available:\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 style)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSD158:\u003c\/strong\u003e 1-5\/8\" shaft (SD taper-lock style)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSK158:\u003c\/strong\u003e 1-5\/8\" shaft (SK taper-lock style)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSK178:\u003c\/strong\u003e 1-7\/8\" shaft (SK taper-lock style)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eMeasure your motor shaft diameter with calipers. Do not assume — measure. The hub bore must match the shaft exactly. Call us if you are unsure which hub series (LX, SD, or SK) your application requires; the series used depends on which was originally installed and what is accessible for your compressor configuration.\u003c\/p\u003e\n\n\u003ch3\u003eWhy This Size Motor Pulley?\u003c\/h3\u003e\n\u003cp\u003eAt 4.55\" OD, this pulley is used on compressors that need to run the pump at a moderate-to-high speed relative to motor RPM — typically mid-sized two-stage compressors where output CFM targets require higher pump RPM than smaller pulleys deliver. The dual B-section grooves handle the torque transmission requirements of larger compressors where a single B-belt would be insufficient. Applications in this range often include 5 HP to 10 HP compressors with two-stage pumps.\u003c\/p\u003e\n\n\u003ch3\u003eDual B-Belt Drive Installation Notes\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eReplace both belts simultaneously:\u003c\/strong\u003e Matched belt pairs only. Mixing a new belt with an old belt creates unequal tension and load distribution.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eVerify pulley alignment:\u003c\/strong\u003e Both pulley grooves on the motor side must align with the corresponding grooves on the pump pulley. Misalignment by even 1\/8\" causes belt edge wear and shortened belt life.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCheck tension on each belt:\u003c\/strong\u003e After initial installation, run the compressor for one hour and re-check tension. New belts stretch slightly during break-in and will need retensioning.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHub installation:\u003c\/strong\u003e Follow Cast Air hub installation instructions. The hub locking screw sequence matters — improper installation can leave the hub slightly off-center, creating runout.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e2B Hub Motor Pulley Lineup\u003c\/h3\u003e\n\u003cul\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  \u003cli\u003e\n\u003cstrong\u003eP2B355H:\u003c\/strong\u003e 3.55\" OD, hub mount — $38.50\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eP2B395H:\u003c\/strong\u003e 3.95\" OD, hub mount — $38.50\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eP2B445H (nearest castair.net listing):\u003c\/strong\u003e 4.45\" OD, hub mount\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eP2B455H (this listing):\u003c\/strong\u003e 4.55\" OD, hub mount — $64.49 (verify before ordering)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eP2B495H:\u003c\/strong\u003e 4.95\" OD, hub mount — $66.41\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 P2B455H (verify — nearest castair.net listing is P2B445H at 4.45\" OD)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOutside Diameter:\u003c\/strong\u003e 4.55\"\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 $64.49 (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\u003eBecause there is an open question on this specific part number — P2B455H vs. P2B445H — we want to talk to you before you complete your order. Our tech support team can pull up the Cast Air documentation, confirm which part is correct for your compressor, and make sure you get the right pulley and the right hub in a single shipment. That is faster and cheaper than ordering the wrong part and waiting for a return and reship.\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 — we will verify P2B455H vs. P2B445H and confirm the right hub for your shaft\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 If there is uncertainty on a part number, we will say so and help you resolve it\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":53342573363413,"sku":"P2B455H","price":119.28,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0622\/8466\/0949\/files\/CastairReplacementAirCompressorPulley.jpg?v=1772652768","url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-replacement-motor-pulley-hub-shaft-4-55-od-2b-grooves","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}