{"product_id":"castair-replacement-industrial-v-type-belt-section-b-length-87-3-b87","title":"Castair Replacement Industrial V-Type Belt Section B Length 87\" 3-B87","description":"\u003cp\u003eThe Castair Replacement Industrial V-Belt, Section B, 87-inch length (SKU: 3-B87) is the correct drive belt for Cast Air compressors spec'd for a B87. It is two inches longer than the B85 — a difference that matters when the motor mounting position or sheave diameter requires that specific circumference to tension correctly. If your machine's data plate, service manual, or OEM parts list specifies B87, this is the belt. If you are not certain of the correct length, measure the old belt or call us before ordering.\u003c\/p\u003e\n\n\u003ch3\u003eBelt Specifications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSection:\u003c\/strong\u003e B (classical B-section)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTop Width:\u003c\/strong\u003e 17\/32 inch (0.53 in)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBelt Depth:\u003c\/strong\u003e 21\/32 inch (0.66 in)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOutside Circumference:\u003c\/strong\u003e 87 inches (B87 designation)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConstruction:\u003c\/strong\u003e Classical wrapped — fabric-wrapped outer cover over a compression rubber body with tension cords running the belt's full length\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompound:\u003c\/strong\u003e Oil-resistant and heat-resistant rubber compound; suited for the operating temperatures and oil mist environment of a reciprocating air compressor drive\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard:\u003c\/strong\u003e Sized per ARPM\/RMA classical belt standards; cross-references to any standard B87 designation from any manufacturer\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eCompatibility and Fit\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSheave groove match:\u003c\/strong\u003e Fits B-section sheave grooves. The B-section profile is not interchangeable with A-section (narrower) or C-section (wider) sheaves. Confirm your sheave is B-section before ordering.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCastair\/Cast Air models:\u003c\/strong\u003e Fits Cast Air compressor models factory-spec'd for the B87 length. The two-inch difference between a B85 and B87 is not trivial — using the wrong length either prevents correct tensioning or results in over-tensioning the bearings. Verify the belt specification from the machine's data plate or service documentation.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConfirming belt length:\u003c\/strong\u003e If the original belt is still on the machine, look for the belt designation molded or printed on the outer face. It will typically read B87 or 5L900 (fractional equivalent). If the belt is gone, calculate from center distance and sheave diameters, or call 866-217-0063 and we will help you work it out.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMatched sets:\u003c\/strong\u003e If the drive runs two belts in parallel, replace both belts at the same time with matched belts. A new belt running alongside a stretched belt will carry disproportionate load and will wear faster than it should.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eInstallation Notes\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCreate slack before seating the belt:\u003c\/strong\u003e Loosen the motor mounting bolts and move the motor toward the compressor pump until there is enough slack to place the belt into the sheave grooves by hand. Never lever or pry the belt over a sheave. That deforms the cross-section and damages the internal tension cord — damage that is invisible until the belt fails prematurely.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTension to spec:\u003c\/strong\u003e The standard deflection method for B-section belts is 1\/2 inch of deflection per foot of free span under approximately 5 lbs of thumb pressure at the belt's mid-span. Adjust motor position and retighten mounting hardware. Do not rely on feel alone — use a tension gauge if available.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCheck alignment:\u003c\/strong\u003e A straightedge laid across both sheave faces should contact both faces flat, with the belt tracking in line. Side loading from misalignment will cause the belt to run hot, wear the edges, and fail in a fraction of its rated service life.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSheave inspection:\u003c\/strong\u003e Before installing the new belt, run your fingers around the sheave grooves. A groove bottom that is shiny or has a channel worn into it by the old belt means the sheave walls are no longer contacting the belt flanks properly. A new belt on a worn sheave will bottom out in the groove, lose grip, and fail early. Replace or re-groove the sheave if it is worn.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBreak-in re-tension:\u003c\/strong\u003e New belts compress and seat during the first few hours of operation. After the first 1-2 hours of run time, shut down and re-check tension. This step is frequently skipped and frequently the cause of \"the new belt slips just like the old one.\"\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBelt dressing sprays:\u003c\/strong\u003e Do not use them. They temporarily mask slippage but do not fix its cause, and they degrade the rubber over time. If a belt is slipping after correct tension and alignment, the belt or sheaves need replacement.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhen to Replace Your Compressor Drive Belt\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eVisible cracking:\u003c\/strong\u003e Surface cracks on the belt back or inner groove face indicate the rubber has hardened and lost elasticity. These cracks will propagate under load. Replace the belt before it fails in service.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGlazed surface:\u003c\/strong\u003e A hard, shiny inner face means the belt has been slipping and overheating. Replace the belt and fix the cause — tension, sheave wear, or alignment.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFraying or raveling at edges:\u003c\/strong\u003e The outer fabric wrap is degrading. The belt is at end of useful life.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSquealing on startup or under load:\u003c\/strong\u003e Startup squeal that clears after a few seconds often means low tension. Squeal that persists with correct tension means the belt surface or sheave faces are glazed.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePump underperformance with motor running:\u003c\/strong\u003e If the motor is running at correct RPM but the pump is not building pressure at the expected rate, and there is no valve or piston issue, check the belt first. A slipping belt is a common and easy-to-miss cause of compressor underperformance.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnnual replacement as PM:\u003c\/strong\u003e On a daily-use shop compressor, replacing the drive belt annually as a matter of scheduled maintenance is cheaper than the lost production time from an unplanned belt failure.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhy Buy From Air Compressor Factory Direct?\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecialist since 2016:\u003c\/strong\u003e Air compressor parts are what we do. We have the product knowledge to help you get the right belt the first time.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFree shipping:\u003c\/strong\u003e Ships free to the contiguous United States.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFree tech support:\u003c\/strong\u003e Call 866-217-0063 with questions about belt sizing, installation, or why a drive keeps eating belts. That conversation costs you nothing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFull manufacturer warranty:\u003c\/strong\u003e Manufacturing defects are covered. If the belt arrives with a defect, we take care of it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHonest guidance:\u003c\/strong\u003e If the B87 is not the right belt for your machine, we will tell you that. Getting you the right part matters more than closing any individual sale.\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":53342506549461,"sku":"3-B87","price":51.12,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0622\/8466\/0949\/files\/beltb_eee90503-3293-47fe-8776-d4cd3daede5e.jpg?v=1772652511","url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-replacement-industrial-v-type-belt-section-b-length-87-3-b87","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}