Everything You Need to Know About Mountain Bike Derailleur

A mountain bike derailleur is an important part of your bike’s chain system. Basically, it is one of the bike’s most hardworking parts. It is responsible for changing the sprockets which transfer the energy from a cyclist’s feet to the wheels when pedaling.

Part 1: Frequently Asked Questions

What is a Derailleur

A derailleur is a bicycle gearing system that consists of a chain, many sprockets of various sizes, and a mechanism for moving the chain from one sprocket to the next.

What is the Function of a Derailleur on a Bike

The derailleur is a gear-shifting device that moves the chain from one sprocket to the next.

Does My Bike Need a Derailleur

Yes, it does. The derailleur is an essential component of your drivetrain and one of the bike’s most hardworking components. Due to these reasons, you must check that it is in good working order and is fully compatible with your bike’s components.

Is it Possible for me to Use any Derailleur on My Bike

A mountain bike derailleur should be compatible with the original derailleur’s specifications. It doesn’t have to be the same kind of derailleur, but it nearly always has to be the same brand. It also has to be the same number of gears as the number of anticipated gears.

How Long does it Take for a Derailleur to Wear Out

At some point, all derailleurs will wear out. A good rear derailleur can last anywhere from 3 to 5 years. Meanwhile, non-branded or low-quality ones can survive up to two years.

What are the Indications of a Worn-out Rear Derailleur

Pull the bottom cage laterally to check for wear. Then, compare this action to that of a brand new derailleur’s linkage. Inconsistent shifting will result from sloppy pivots and connections, and the only option is to replace the derailleur.

Where is the Location of the Derailleur on a Bike

A bike has two derailleurs, one at the front and one on the rear. When the chain is on the largest sprocket in the front and the smallest in the rear, the highest ratio (when the bike can travel the fastest) is created.

Is it Possible to Repair a Bent Derailleur

You have two alternatives here: either bend the hanger back into place or replace it with a new one.

How to Check the Rear Derailleur

You can use a hanger alignment tool. This tool replaces the rear derailleur on the hanger and facilitates adjustment inspections against the rim. This tool also allows you to correct the alignment by rebending the hanger.

Is it Possible to Ride a Bike without Either a Derailleur

A mountain bike can technically function without a derailleur. You may arrange your derailleur to keep the bike running if it breaks. You may, however, remove it entirely and make it a single-speed bike if you like.

Part 2: Data Comparison

If mountain biking is your passion, then you need to get a suitable derailleur for your bike. In order to make it easy for you to see the specifications offered by some different products, we provide you with a data comparison about the mtb derailleur. Check it out!


Weight: 290G
Total Capacity: 40T
Price: $128.00

Shimano Deore XT RD M-786

Weight: 284G
Total Capacity: 41T

microSHIFT Advent X

Weight: 350G
Total Capacity: 41T
Price: $91.19

Shimano XT RD M-8000

Weight: 400G
Total Capacity: 39T
Price: $99.99

SRAM X.4 Rear Derailleur

Weight: 310G
Total Capacity: 45T
Price: $30.57


Weight: 330G
Total Capacity: 41T
Price: $73.99

Shimano RD-M640 Zee Shadow Plus

Weight: 362G
Total Capacity: 25T
Price: $59.99-$95.13

Shimano Acera RD M-360 SGS

Weight: 300G
Total Capacity: 43T
Price: $24.94

Part 3: Conclusion

As mentioned above, a bicycle derailleur is one of the important parts of every bicycle. It has a direct impact on a rider’s speed and distance covered. The biker will adjust the chain between several sprockets depending on the riding conditions. Sprockets transfer the energy from a cyclist’s feet to the wheels when they pedal. One of these sprockets is just next to the pedal, and the other is at the back wheel. There is one sprocket each in a single-speed bicycle.

However, there could be multiple sprockets at each end of a multi-speed cycle. The cassettes, a series of sprockets, are placed symmetrically in order. When you think it is time to change the derailleur of your mountain bike, go to a bike shop and choose a good mountain bike derailleur, preferably from the same brand as your mtb.

Part 4: Detailed Introduction of Each Product & Advantages and Disadvantages

The three major companies in the drivetrain market are Shimano, SRAM, and Campagnolo. They make good products of derailleurs that become the ultimate choice of most MTB riders. Groupset components are also made by Microshift, Box, Rotor, FSA, and others. However, the final choice depends on the kind of bike you ride. All things considered, below are some options for you to choose to purchase a good mountain bike derailleur for your MTB.

mountain bike derailleur


This SRAM rear derailleur delivers the quality of significantly greater models at a lower cost. It’s designed to ensure precise and speedy gear shifting despite trail conditions. It may be used with a variety of gears, allowing you to switch precisely and quickly on any path. Undoubtedly, it’s one of the greatest derailleurs on the market, and it’ll save you time and energy no matter how difficult the route is.

It also maintains your mtb steady by keeping the chain tension stable. Because of the enclosed cartridge bearings, the design enables simple and quick installation. It secures the derailleur kept out of the way and allows for easy assembly and disassembly because it doesn’t interact with the wheel. But, there is one thing you need to pay attention to: you must be cautious when installing it; otherwise, it may break.

Shimano Deore XT RD M-786

The Deore XT RD-M786 can accept a large gear range thanks to its maximum chain wrap capacity of 43T. The word “smooth switching” perfectly describes this derailleur. You may increase spring tension using a switch on Shimano’s new clutch system featured on this model. Shifting is now easier, more steady, and quieter. Even on bumpy and muddy roads, this derailleur keeps the chain from bouncing or hitting against the sprocket.

This ensures constant shifting no matter what terrain. The Deore XT RD-M786 can handle a wide range of gears due to its maximum chain wrap capacity of 43T. With this much gear selection, you may enjoy a nice flat ride as well as a smooth hill climb. Aside from the advantages mentioned above, it’s too bad that this mtb derailleur needs a separate derailleur for 1x and 2x.

microSHIFT Advent X

The upper edge microSHIFT Advent X rear derailleur combines excellent performance with a race-worthy weight and the ideal gearing for any circumstances. Even in the most difficult conditions, Advent X can help you discover the proper gear. By combining a 10-speed chain with a wide-range 11-48t cassette with predictable, uniformly spaced gear steps, you may achieve a wide variety of speeds. It features a revolutionary ratchet-and-pawl clutch, solid metal construction, and convenience features such as metric hardware for easy setup.

The ratchet-and-pawl clutch secures the chain and may be switched on and off. Look no further if you want an outstanding quality without the need for new standards or proprietary parts. There are some drawbacks of this mtb derailleur though. The shifts aren’t the crispest; lever travel is considerable before the switch engages; shifter ergonomics may not be to everyone’s liking.

Shimano XT RD M-8000

With superb chain stability, the Shimano XT RD-M8000 rear derailleur enables immediate shifting and smooth operation. The shadow clutch prevents chain slap and dropped chains, while the on-off switch makes wheel swaps simple. Even for novice cyclists, this gear shift might come in handy when descending or ascending difficult-to-manage terrain. Also, it includes a total of 11-speed transmission gears that are simple for riders to operate.

It features a direct mount, which negates the need for a link while also reducing flex, weight, and damage on the bike. The overall measurements of this mountain bike derailleur are 6 x 6 x 4 inches. From start to end, the product is made entirely of lightweight real aluminum components. You don’t need any special skills or tools to install this derailleur on your bike. Too bad, there is no barrel adjuster included with the product.

SRAM X.4 Rear Derailleur

The item is black and has Shimano/SRAM 9 drivetrain spacing with a 34 teeth biggest cog. The SRAM X.4 rear derailleur comes with an SGS-long casing. The product measures 17.9 x 13.4 x 10.4 inches in size. It’s lightweight, and the entire weight of the instrument is only 4.2 ounces, making it acceptable for even teen mountain bikes. You wouldn’t need to go out and get new tools because the standard ones would suffice for installing this derailleur.

After installing it on your mountain bike, you won’t have any problems since the product is simple to maintain. Those interested in purchasing it can rest confident that it will not require specialist installation on their dirt bikes. Only one thing is missing, there are no installation instructions included.


The XCD is a medium-cage derailleur that can accommodate cassettes up to 46T. A ratchet-and-pawl clutch arrangement is also included for improved chain retention. Basically, the microSHIFT is an alternative for a Shimano-equipped bike if you want high-end shifting for less money. The microSHIFT XCD has a clutch tension control that is wrapped in rubber. The chain tension is maintained by the serviceable clutch mechanism.

Shimano mountain shifters and wide-range cassettes are compatible with XCD rear derailleurs. You can power up and down through a range of terrains thanks to CNC-machined sturdy structure and improved chain stability. Unfortunately, a separate derailleur is required for 1x and 2x.

Shimano RD-M640 Zee Shadow Plus

Shimano’s RD-M640 mountain bike derailleur features a low-profile shape and a streamlined design. The Zee RD 640 features Shadow Plus Technology, which decreases chain slap, drops, and impacts noise. Particularly, Zee is ready to tackle the needs of enduro and downhill racers with two standard options that permit a regular MTB cassette or a close-ratio road cassette. Moreover, the Zee rear derailleur is built to withstand the demands of heavy downhill riding and sets a new bar for performance and durability.

It includes a shadow plus cage tensioner to reduce chain bounce and silence the gearbox. It’s an extremely flexible short cage derailleur that handles all terrain excellently. Also, the Zee is simple to install and establish. It’s compatible with other Shimano items from the same line as well as other Shimano family members. However, the derailleur’s instructions are a little bit hazy as they reference general derailleurs instead of this specific one. The only problem is there is no triple support.

Shimano Acera RD M-360 SGS

The Shimano Acera RD M-360 SGS is built of durable aluminum metal that can handle harsh riding circumstances such as mountain trails and off-road biking. It has a lengthy cage that makes it suitable for a variety of bike models, designs, and manufacturers. Even new riders may easily alter the chain’s 7/8 speed selections during mountainous steep climbs and descents. This mountain bike rear derailleur has a chain wrap capacity of 43 teeth, making even the most arduous journeys easy for riders.

The top-normal kind of derailleur operation is suited to all dirt bikes. It’s also lightweight, at only 7 ounces, making it ideal for smaller teen bicycles. You can install it on practically all mountain bike types and models. But, there is a minus: a hanger is not included in the package and must be ordered separately from the bike manufacturer.