---
product_id: 481941776
title: "Acera RD-M3020-SGS Rear Derailleur - 7/8 Speed, Long Cage, Black"
brand: "shimano"
price: "¥11554"
currency: JPY
in_stock: true
category: "Shimano"
url: https://www.desertcart.jp/products/481941776-acera-rd-m3020-sgs-rear-derailleur-7-8-speed-long
store_origin: JP
region: Japan
---

# Long cage with 45T chain wrap capacity Double Servo mechanism for precision shifting Compatible with 7/8 speed drivetrains Acera RD-M3020-SGS Rear Derailleur - 7/8 Speed, Long Cage, Black

**Brand:** shimano
**Price:** ¥11554
**Availability:** ✅ In Stock

## Summary

> ⚡ Shift Like a Pro, Ride Like You Own the Road!

## Quick Answers

- **What is this?** Acera RD-M3020-SGS Rear Derailleur - 7/8 Speed, Long Cage, Black by shimano
- **How much does it cost?** ¥11554 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.jp](https://www.desertcart.jp/products/481941776-acera-rd-m3020-sgs-rear-derailleur-7-8-speed-long)

## 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

- • **Extended Gear Range:** Long cage design handles up to 45 teeth, perfect for tackling varied terrains.
- • **Trusted Performance:** Backed by Shimano’s 2-year warranty and a stellar 4.7-star rating from riders worldwide.
- • **Lightweight Durability:** Crafted from robust aluminum, balancing strength with minimal weight (0.39 kg).
- • **Versatile Compatibility:** Seamlessly fits 7 and 8-speed drivetrains for broad bike compatibility.
- • **Precision Shifting Mastery:** Double Servo mechanism ensures ultra-smooth, accurate gear changes every ride.

## Overview

The Shimano Acera RD-M3020-SGS Rear Derailleur is a high-performance, long-cage derailleur designed for 7 and 8-speed drivetrains. Featuring Shimano’s Double Servo mechanism for precise shifting and a 45-tooth chain wrap capacity, it offers versatile compatibility and durability with its lightweight aluminum construction. Ideal for cyclists seeking reliable, smooth gear transitions backed by a trusted 2-year warranty.

## Description

desertcart.com : Shimano Acera RD-M3020-SGS Rear Derailleur - 7/8 Speed, Long Cage, Black : Sports & Outdoors

## Features

- Double Servo mechanism enables the rear derailleur to move in an optimum path
- Versatile performance and wide compatibility
- SGS Long cage
- Chain Wrap Capacity (teeth): 45
- Drivetrain Speeds: 7,8

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B0BGFBSYQ3 |
| Best Sellers Rank | #73,500 in Sports & Outdoors ( See Top 100 in Sports & Outdoors ) #29 in Rear Bike Derailleurs |
| Brand | SHIMANO |
| Brand Name | SHIMANO |
| Case Material Type | Aluminum |
| Color | Black |
| Customer Reviews | 4.7 out of 5 stars 189 Reviews |
| Included Components | Rear Derailleur |
| Item Weight | 0.39 Kilograms |
| Manufacturer | Shimano |
| Manufacturer Part Number | ERDM30208SGSL |
| Material | Aluminum |
| Material Type | Aluminum |
| Model Number | ERDM30208SGSL |
| Mount Type | Braze-On Mount |
| Mounting Type | Braze-On Mount |
| Number of Teeth | 45 |
| UPC | 192790897738 |
| Warranty Description | 2 years |

## Product Details

- **Brand:** SHIMANO
- **Color:** Black
- **Item Weight:** 0.39 kg
- **Material:** Aluminum
- **Mounting Type:** Braze-On Mount

## Images

![Acera RD-M3020-SGS Rear Derailleur - 7/8 Speed, Long Cage, Black - Image 1](https://m.media-amazon.com/images/I/61LquuwOcdL.jpg)

## Questions & Answers

**Q: Will this replace stx rc?**
A: Yes it will as long as your low sprocket on your cassette is as least a 30t.  There are cheaper Shimano derailleurs that will also work.  What makes this one special is it can be used on a 1x setup with a 11-40T cassette.

**Q: Will this replace an sis megarange?**
A: A highly qualified "Yes". Be prepared to become a self-taught expert in bicycle derailleurs in the process. Expect to discover that you need other parts, such as a hanger-adapter. You will almost certainly need to replace your shifter cable and housing, as the cable entry is different, necessitating rerouting, and hence a different length cable and housing.

## Frequently Bought Together

- Shimano Acera RD-M3020-SGS Rear Derailleur - 7/8 Speed, Long Cage, Black
- KMC Chain 8SP X8-Silver/Grey - X8.93
- SHIMANO Unisex Cshg4008140 CS HG400 8 Speed Cassette 11 40T, Silver, 40 Teeth UK

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**Shop now:** [https://www.desertcart.jp/products/481941776-acera-rd-m3020-sgs-rear-derailleur-7-8-speed-long](https://www.desertcart.jp/products/481941776-acera-rd-m3020-sgs-rear-derailleur-7-8-speed-long)

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*Product available on Desertcart Japan*
*Store origin: JP*
*Last updated: 2026-08-17*