---
product_id: 158810962
title: "SHIMANO XT RD-M8100-SGS RD-M8120-SGS 12-Speed Rear Derailleur, Long Cage, Black"
brand: "shimano"
price: "$243.28"
currency: USD
in_stock: true
reviews_count: 12
url: https://www.desertcart.us/products/158810962-shimano-xt-rd-m8100-sgs-rd-m8120-sgs-12-speed
store_origin: US
region: United States of America
---

# Long cage for 2x12 setups 12-speed precision shifting Shadow+ chain stability tech SHIMANO XT RD-M8100-SGS RD-M8120-SGS 12-Speed Rear Derailleur, Long Cage, Black

**Brand:** shimano
**Price:** $243.28
**Availability:** ✅ In Stock

## Summary

> ⚡ Shift like a pro, ride like a legend.

## Quick Answers

- **What is this?** SHIMANO XT RD-M8100-SGS RD-M8120-SGS 12-Speed Rear Derailleur, Long Cage, Black by shimano
- **How much does it cost?** $243.28 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.us](https://www.desertcart.us/products/158810962-shimano-xt-rd-m8100-sgs-rd-m8120-sgs-12-speed)

## Best For

- shimano enthusiasts

## Why This Product

- Trusted shimano brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Plug-and-Play Upgrade:** Out-of-the-box performance with minimal adjustment—upgrade your ride instantly.
- • **Shadow+ Chain Retention:** Advanced tech minimizes chain slap and noise, ensuring a whisper-quiet ride.
- • **Durable Alloy Steel Build:** Robust construction designed to withstand rugged mountain biking conditions.
- • **Optimized Long Cage Design:** Perfectly engineered for 2x12 drivetrains, delivering flawless chain management.
- • **Seamless 12-Speed Shifting:** Experience ultra-smooth, shock-free gear changes that keep you ahead on every trail.

## Overview

The Shimano Deore XT RD-M8100-SGS/RD-M8120-SGS is a premium 12-speed long cage rear derailleur engineered for mountain biking. Featuring Shadow+ technology for stable, quiet chain retention and a durable alloy steel build, it delivers precise, shock-free shifting optimized for 2x12 drivetrain setups. Trusted by enthusiasts for seamless upgrades and reliable performance on demanding trails.

## Description

The Shimano Deore XT RD-M8100/M8120 rear derailleur is designed to provide smooth and stable shifting for 12-speed MTB transmissions. Delivers fast and shock-free change. Low profile design includes an added bumper to the derailleur pulley cage Shimano Shadow RD+ technology reduces chain shock and creates a quieter transmission Includes large 13 ton pulley The long cage is designed to be used with 2x12 transmission systems.

Review: Genuine - Replaced a completely mangled one after a boulder strike - good value
Review: Well worth the Upgarde - Upgraded from Sram XS system to this Shimano XT RD-M8100-SGS RD-M8120-SGS 12-Speed Rear Derailleur, Long Cage also with Shimano XT8100 shifter and just wow so much smoother this is when changing gears and it just works straight out the box when fitted a little adjustment was needed but not as much with the Sram. Well worth the upgrade

## Features

- Deore XT RD-M8100 12-speed rear derailleur for precise gear shifting
- Shimano brand ensures quality and performance
- Shadow+ design for stable chain retention
- Suitable for single chainring setups

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B07SWQZB46 |
| Best Sellers Rank | 62,068 in Sports & Outdoors ( See Top 100 in Sports & Outdoors ) 63 in Bike Rear Dérailleurs |
| Brand Name | SHIMANO |
| Case Material Type | Alloy Steel |
| Colour | Black |
| Customer Reviews | 4.7 4.7 out of 5 stars (560) |
| Global Trade Identification Number | 04550170443641 |
| Included Components | Shimano Deore XT |
| Item Dimensions L x W x H | 17.8L x 17.8W x 12.7H centimetres |
| Item Type Name | Brakes & Shifters |
| Item Weight | 200 Grams |
| League Name | Shimano |
| Manufacturer | Shimano Deore XT |
| Manufacturer Part Number | 587830 |
| Manufacturer Warranty Description | 1 year manufacturer |
| Material Type | Other |
| Model Number | 587830 |
| Mount Type | Clamp-On Mount |
| Number of Teeth | 26 |
| UPC | 192790443645 |

## Product Details

- **Brand:** SHIMANO
- **Colour:** Black
- **Item weight:** 200 Grams
- **League:** Shimano
- **Material:** Other

## Images

![SHIMANO XT RD-M8100-SGS RD-M8120-SGS 12-Speed Rear Derailleur, Long Cage, Black - Image 1](https://m.media-amazon.com/images/I/51K46DNzSPL.jpg)
![SHIMANO XT RD-M8100-SGS RD-M8120-SGS 12-Speed Rear Derailleur, Long Cage, Black - Image 2](https://m.media-amazon.com/images/I/51IwDQXeFdL.jpg)

## Available Options

This product comes in different **Size** options.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Genuine
*by M***. on 15 May 2025*

Replaced a completely mangled one after a boulder strike - good value

### ⭐⭐⭐⭐⭐ Well worth the Upgarde
*by M***S on 6 October 2024*

Upgraded from Sram XS system to this Shimano XT RD-M8100-SGS RD-M8120-SGS 12-Speed Rear Derailleur, Long Cage also with Shimano XT8100 shifter and just wow so much smoother this is when changing gears and it just works straight out the box when fitted a little adjustment was needed but not as much with the Sram. Well worth the upgrade

### ⭐⭐⭐⭐⭐ Superb
*by T***K on 25 July 2024*

The usual super Shimano quality. The shifting is crisp and accurate and installed without issue , i always default to Shimano XT. im a very happy cyclist

## Frequently Bought Together

- SHIMANO XT RD-M8100-SGS RD-M8120-SGS 12-Speed Rear Derailleur, Long Cage, Black
- Shimano XT SL-M8100-L Right Clamp-Band 12-Speed Shifter, Black
- SHIMANO Xt Cs-M8100 12-Speed Cassette

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*Product available on Desertcart United States of America*
*Store origin: US*
*Last updated: 2026-05-19*