{"product_id":"harley-davidson-x440-x440t-rear-brake-disc-hdh43251raa000s","title":"Harley-Davidson X440 \/ X440T Rear Brake Disc HDH43251RAA000S | Genuine 240mm Rear Rotor","description":"\u003ch2\u003eHarley-Davidson X440 \/ X440T Rear Brake Disc – HDH43251RAA000S\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eReplace a worn, scored, warped, heat-damaged or accident-damaged rear brake rotor with the correct genuine Harley-Davidson rear brake disc.\u003c\/strong\u003e Part number \u003cstrong\u003eHDH43251RAA000S\u003c\/strong\u003e is identified in the supplied parts catalogues as \u003cstrong\u003eDISC RR BRAKE\u003c\/strong\u003e \/ rear brake disc. In buyer-friendly terminology, this is the \u003cstrong\u003erear brake disc\u003c\/strong\u003e, \u003cstrong\u003erear brake rotor\u003c\/strong\u003e, or \u003cstrong\u003erear disc plate\u003c\/strong\u003e used on the Harley-Davidson X440 family applications confirmed below.\u003c\/p\u003e\n\n\u003cp\u003eThis listing is written around the terms owners and workshops are most likely to search for, including \u003cstrong\u003eHarley X440 rear brake disc\u003c\/strong\u003e, \u003cstrong\u003eX440 rear brake rotor\u003c\/strong\u003e, \u003cstrong\u003eHarley X440T rear disc\u003c\/strong\u003e, \u003cstrong\u003eX440T rear brake rotor\u003c\/strong\u003e, \u003cstrong\u003e240mm rear brake disc X440\u003c\/strong\u003e, and the exact OEM part number \u003cstrong\u003eHDH43251RAA000S\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003ch3\u003eProduct Identity\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Harley-Davidson\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e HDH43251RAA000S\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOfficial Catalogue Description:\u003c\/strong\u003e DISC RR BRAKE\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCommon Name:\u003c\/strong\u003e Rear Brake Disc \/ Rear Brake Rotor \/ Rear Disc Plate\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePosition:\u003c\/strong\u003e Rear wheel\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrake Type:\u003c\/strong\u003e Disc brake\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNominal Rear Disc Size:\u003c\/strong\u003e 240 mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eQuantity:\u003c\/strong\u003e 1 piece\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eConfirmed Compatibility\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eHarley-Davidson X440 – September 2023\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eHarley-Davidson X440T – January 2026 \/ R4AA\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cstrong\u003eCompatibility note:\u003c\/strong\u003e the same exact part number appears in both the supplied September 2023 X440 catalogue and the January 2026 X440T catalogue, confirming cross-model fitment for these two applications. Fitment to any other model or generation should still be checked by exact OEM part number before ordering.\u003c\/p\u003e\n\n\u003ch3\u003eRear Brake Disc Specification Context\u003c\/h3\u003e\n\u003cp\u003eHarley-Davidson \/ Hero published specifications for both the X440 and X440T list a \u003cstrong\u003e240 mm rear disc brake\u003c\/strong\u003e. This makes the catalogue identification consistent with the factory chassis specification for these models.\u003c\/p\u003e\n\n\u003ch3\u003eWhat This Part Does\u003c\/h3\u003e\n\u003cp\u003eThe rear brake disc is the rotating braking surface attached to the rear wheel. When the rear brake is applied, the brake pads clamp the disc through the caliper to create braking force. Because the disc is a critical friction surface, correct thickness, flatness, mounting and surface condition are essential for predictable braking performance.\u003c\/p\u003e\n\n\u003ch3\u003eCommon Reasons for Replacement\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eBrake disc is warped or causing pulsation\u003c\/li\u003e\n\u003cli\u003eRotor has deep scoring or grooves\u003c\/li\u003e\n\u003cli\u003eDisc is below service thickness\u003c\/li\u003e\n\u003cli\u003eSurface has been damaged by worn brake pads\u003c\/li\u003e\n\u003cli\u003eDisc is bent after an accident or wheel impact\u003c\/li\u003e\n\u003cli\u003eHeat spots, cracking or severe discoloration are present\u003c\/li\u003e\n\u003cli\u003eRear brake overhaul requires replacement of a damaged rotor\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSymptoms of a Damaged Rear Brake Disc\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003ePulsation or uneven braking at the rear wheel\u003c\/li\u003e\n\u003cli\u003eScraping or grinding noise during braking\u003c\/li\u003e\n\u003cli\u003eVisible scoring, grooves or impact damage\u003c\/li\u003e\n\u003cli\u003eBrake pads wearing unevenly\u003c\/li\u003e\n\u003cli\u003eRear brake lever \/ pedal feel becoming inconsistent\u003c\/li\u003e\n\u003cli\u003eDisc visibly running out of true when the wheel rotates\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eImportant – Disc Only\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eHDH43251RAA000S is the rear brake disc \/ rotor only.\u003c\/strong\u003e It is not a complete rear brake kit.\u003c\/p\u003e\n\n\u003cp\u003eDo not confuse this item with:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eRear brake caliper\u003c\/li\u003e\n\u003cli\u003eRear brake pads\u003c\/li\u003e\n\u003cli\u003eRear ABS sensor ring \/ tone ring\u003c\/li\u003e\n\u003cli\u003eRear wheel-speed sensor\u003c\/li\u003e\n\u003cli\u003eRear brake hose\u003c\/li\u003e\n\u003cli\u003eRear master cylinder\u003c\/li\u003e\n\u003cli\u003eComplete rear wheel assembly\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eRelated Rear-Brake Components\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eHDH43250ACJ000S\u003c\/strong\u003e – Caliper Sub Assy\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHDH43251RAA000S\u003c\/strong\u003e – Disc RR Brake – this product\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHDH43252ACD000S\u003c\/strong\u003e – Sensor Ring Rear \/ ABS tone ring\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHDH43301AABA00S\u003c\/strong\u003e – Clip, Brake Line\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHDH43310ACJ000023S\u003c\/strong\u003e – Clamper A RR Brake\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHDH43331AACJ000S\u003c\/strong\u003e – Rear Brake Hose Sub Assembly\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhy Exact Part-Number Matching Matters\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eBrake discs can share similar diameters but differ in bolt pattern, offset or carrier geometry\u003c\/li\u003e\n\u003cli\u003eIncorrect rotor offset can affect caliper alignment\u003c\/li\u003e\n\u003cli\u003eABS-equipped motorcycles require correct relationship between brake and wheel-speed components\u003c\/li\u003e\n\u003cli\u003eExact OEM part-number matching reduces fitment risk\u003c\/li\u003e\n\u003cli\u003eCorrect genuine replacement avoids modification or spacer improvisation\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat’s in the Box\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e1 x Genuine Harley-Davidson Rear Brake Disc \/ Rotor\u003c\/li\u003e\n\u003cli\u003ePart number: \u003cstrong\u003eHDH43251RAA000S\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eNot Included Unless Specifically Supplied\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eBrake pads\u003c\/li\u003e\n\u003cli\u003eCaliper\u003c\/li\u003e\n\u003cli\u003eABS sensor ring\u003c\/li\u003e\n\u003cli\u003eWheel-speed sensor\u003c\/li\u003e\n\u003cli\u003eDisc mounting bolts\u003c\/li\u003e\n\u003cli\u003eRear wheel\u003c\/li\u003e\n\u003cli\u003eBrake hose or master cylinder\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eInstallation \u0026amp; Inspection Notes\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eInspect rear brake pads when replacing the disc\u003c\/li\u003e\n\u003cli\u003eCheck the caliper slides \/ movement and pad contact pattern\u003c\/li\u003e\n\u003cli\u003eInspect the rear ABS sensor ring and sensor for damage\u003c\/li\u003e\n\u003cli\u003eClean the new braking surface before use\u003c\/li\u003e\n\u003cli\u003eEnsure the disc mounting face is clean and free from debris\u003c\/li\u003e\n\u003cli\u003eTighten mounting fasteners to the correct workshop specification\u003c\/li\u003e\n\u003cli\u003eCheck disc runout after installation\u003c\/li\u003e\n\u003cli\u003eBed in new pads \/ disc correctly where required\u003c\/li\u003e\n\u003cli\u003eBrake-system work should be performed by a competent technician\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eBrake Safety Note\u003c\/h3\u003e\n\u003cp\u003eThe brake disc is a safety-critical component. Do not continue using a rotor that is cracked, severely warped, below minimum service thickness or otherwise structurally damaged. If the cause of abnormal brake wear is unclear, inspect the full rear brake system before replacing parts.\u003c\/p\u003e\n\n\u003ch3\u003eReturn Prevention Note\u003c\/h3\u003e\n\u003cp\u003ePlease verify that you need the \u003cstrong\u003eREAR BRAKE DISC \/ DISC RR BRAKE\u003c\/strong\u003e and not the rear ABS sensor ring. The two parts sit close to each other in the rear-wheel assembly but serve completely different functions.\u003c\/p\u003e\n\n\u003ch3\u003eFAQs\u003c\/h3\u003e\n\n\u003cp\u003e\u003cstrong\u003e1. What is HDH43251RAA000S?\u003c\/strong\u003e\u003cbr\u003e\nIt is the genuine \u003cstrong\u003erear brake disc \/ rear brake rotor\u003c\/strong\u003e used in the confirmed Harley-Davidson X440 and X440T applications.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003e2. Which models are confirmed?\u003c\/strong\u003e\u003cbr\u003e\nThe supplied catalogues confirm \u003cstrong\u003eHarley-Davidson X440 – September 2023\u003c\/strong\u003e and \u003cstrong\u003eHarley-Davidson X440T – January 2026 \/ R4AA\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003e3. What size is the rear brake disc?\u003c\/strong\u003e\u003cbr\u003e\nHarley-Davidson \/ Hero specifications for the X440 and X440T list a \u003cstrong\u003e240 mm rear disc brake\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003e4. Is this the rear ABS sensor ring?\u003c\/strong\u003e\u003cbr\u003e\nNo. The ABS sensor ring is a separate part. \u003cstrong\u003eHDH43251RAA000S\u003c\/strong\u003e is the brake rotor itself.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003e5. Does the disc include brake pads?\u003c\/strong\u003e\u003cbr\u003e\nNo. Brake pads are separate service parts.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003e6. Can a warped rear disc cause pulsation?\u003c\/strong\u003e\u003cbr\u003e\nYes. Excessive disc runout or distortion can cause uneven braking and pulsation.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003e7. Should pads be checked when replacing the disc?\u003c\/strong\u003e\u003cbr\u003e\nYes. Worn, glazed or uneven pads can damage a new disc or prevent proper bedding-in.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003e8. Does it fit X440 OBDII?\u003c\/strong\u003e\u003cbr\u003e\nThe supplied screenshots directly confirm the September 2023 X440 and January 2026 X440T. X440 OBDII fitment should be confirmed separately by exact catalogue reference before ordering.\u003c\/p\u003e\n\n\u003ch3\u003eSearch Keywords\u003c\/h3\u003e\n\u003cp\u003eHarley X440 rear brake disc, X440 rear brake rotor, Harley X440T rear brake disc, X440T rear rotor, 240mm rear brake disc X440, rear disc plate Harley X440, DISC RR BRAKE, HDH43251RAA000S.\u003c\/p\u003e","brand":"Harley-Davidson","offers":[{"title":"Default Title","offer_id":52186688225575,"sku":"HDH43251RAA000S","price":2362.0,"currency_code":"INR","in_stock":true}],"url":"https:\/\/underthehood.co.in\/products\/harley-davidson-x440-x440t-rear-brake-disc-hdh43251raa000s","provider":"UNDER THE HOOD","version":"1.0","type":"link"}