{"product_id":"shimano-deore-xt-rd-m8100-sgs-rear-derailleur-12-speed","title":"Shimano Deore XT RD-M8100-SGS Rear Derailleur | 1x12-Speed","description":"\u003ch2\u003eShimano Deore XT RD-M8100-SGS Rear Derailleur — 1x12-Speed\u003c\/h2\u003e\n\u003cp\u003eThis is the SGS long-cage version of Shimano's Deore XT M8100 rear derailleur, built for a compatible mechanical 1x12 mountain-bike drivetrain with a 10–51T cassette. The exact product code is IRDM8100SGS. Choosing the right cage version matters: this listing is the long-cage model for the 51-tooth largest sprocket.\u003c\/p\u003e\n\u003ch3\u003eWhat it does on the bike\u003c\/h3\u003e\n\u003cp\u003eA rear derailleur guides the chain between cassette sprockets and takes up chain slack as you change gears. Here, 1x12 means one front chainring and twelve rear sprockets. The long cage manages the chain-length difference across the wide cassette range.\u003c\/p\u003e\n\u003cp\u003eSHADOW RD+ helps control cage movement over rough ground, while the low-profile layout keeps the derailleur tucked closer to the bike. The pulley-cage bumper helps reduce impact noise. Two 13-tooth pulleys guide the chain, with sealed bearings in the guide and tension pulleys.\u003c\/p\u003e\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eSeries: Shimano Deore XT M8100\u003c\/li\u003e\n\u003cli\u003eModel: RD-M8100-SGS; long cage\u003c\/li\u003e\n\u003cli\u003eDrivetrain: compatible mechanical 1x12-speed MTB system\u003c\/li\u003e\n\u003cli\u003eIntended cassette range: 10–51T\u003c\/li\u003e\n\u003cli\u003eTotal capacity: 41T; front chainring difference: 0T\u003c\/li\u003e\n\u003cli\u003eChain stabilizer: SHADOW RD+\u003c\/li\u003e\n\u003cli\u003ePulleys: 13 teeth; sealed guide and tension pulley bearings\u003c\/li\u003e\n\u003cli\u003eManufacturer average weight: 284 g\u003c\/li\u003e\n\u003cli\u003eProduct code: IRDM8100SGS; UPC: 192790443645\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCompatibility comes before the speed count\u003c\/h3\u003e\n\u003cp\u003eMatch the shifter, chain and cassette to Shimano's compatible 12-speed MTB system. Twelve speeds alone does not establish compatibility with road controls, other brands or electronic shifting. Check your frame's derailleur hanger and mounting arrangement as well.\u003c\/p\u003e\n\u003cp\u003eWhen replacing a damaged derailleur, inspect hanger alignment. Correct chain length and derailleur adjustment are still needed for clean shifts, even with a new part.\u003c\/p\u003e\n\u003ch3\u003eCommon questions\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs this a Di2 derailleur?\u003c\/strong\u003e No. This is the mechanical, cable-operated model.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs it for a double chainring?\u003c\/strong\u003e No. This SGS model is specified for a single front chainring.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes the listing include a cassette or shifter?\u003c\/strong\u003e No. It is one rear derailleur; other drivetrain components are separate.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eUnsure about fit?\u003c\/strong\u003e Send Go Grava your shifter model, cassette range and current derailleur model before ordering.\u003c\/p\u003e","brand":"Shimano","offers":[{"title":"Default Title","offer_id":54031694135610,"sku":"GG-SHIM-RD-M8100-SGS","price":145.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0745\/5735\/8394\/files\/330e4d7d2ec8184b6f3306dbffe2f49753f9fc03.png?v=1788911777","url":"https:\/\/gograva.com\/products\/shimano-deore-xt-rd-m8100-sgs-rear-derailleur-12-speed","provider":"Grava Adventure Corporation","version":"1.0","type":"link"}