Mountain Bike Drivetrain Explained

The drivetrain or group set is one of the most important parts of any mountain bike. Once you have a grasp of the components, you can find the right one for your needs and you will also know how to make repairs on the fly. Many people have mountain bikes, but they have no idea how the bicycle drivetrain are set up or how they work.

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In the following article, we will have a closer look at the mountain bike drivetrain and try to explain some of the intricate components that make them stand out. By the time you have read this article, you should be able to look at drivetrains and know what each of the components means or how they are commonly used.

Drivetrain Components:

mtb drivetrain

To get a grip on the mountain bike drivetrain, you will need to understand what they are and how they are comprised. There are numerous small components of the drivetrain that are important to the drivetrain, which needs to be understood. Here is a small breakdown of each component of the standard drivetrain.

• Crankset: The crankset is probably one of the most important parts of the drivetrain and it is located near the sides of the pedals. The goal of the crankset is to control the larger speeds of the drivetrain and is generally 1 to 3 chainrings. These chainrings are pretty standard to mountain bikes in terms of size, but they vary when it comes to the number that is fitted to each bike.

• Cassette: The cogs found at the rear of the bike, which forms part of the chain are called the cassette. These cassettes can often be referred to like the smaller or minor gears of the mountain bike and there is often between 8 and 12 of these cogs on each of the rear elements of the drivetrain. They are important in controlling the speeds of the bike.

• Derailleurs: All mountain bike drivetrains will have two derailleurs. These small components are located at the front and rear of the cassettes. The derailleur has one responsibility and this responsibility is to shift the chain from one chainring to the other. It is controlled by the shifters, which are located on the front of the handlebars.

• Chain: One of the biggest components is the chain that holds the front and rear cassettes together while making them functional. The chain of a mountain bike drivetrain is pretty standard and it has a goal of changing the difficulty of pedaling and to provide more resistance. However, it is also the weakest part of the drivetrain, which can break or snap off when not maintained.

• Shifters: All of these components need some form of control that is provided by the user. Since you will be riding the mountain bike, you need some form of control to ensure that you can change the gears and shift them accordingly. Shifters are located on the handlebars and will put the power in your hands to ensure you have the right speed.

Not all shifters are the same and you will notice that micro shifters are the most common for a mountain bike. However, entry-level bikes can also have the twist-shifters, which is simply a knob that will adjust the chain. The downside to twist-shifters is their reliability and these shifters are not ideal when trekking through tough and muddy conditions.

Gear Ratios And Numbers:

Once you have a basic understanding of the components, you need to understand some of the numbers. Much like any components, it all comes down to numbers and you will need to know how to use these numbers. IT is best to start with the gear ratios to see how they are used and what purpose they serve for the rider.

• Higher Gear Ratios: Using higher gear ratios is ideal for generating speed on the mountain bike. The wheel will make more revolutions with every pedal, which means that you will be moving forward at a much faster pace. Higher gear ratios will allow the bike to build up a bit more momentum, which means you have less pedaling to do once you reach top speeds.

• Lower Gear Ratios: Lower gear ratios have the opposite effect and they provide less friction from the tire to the surface of the terrain. Lower gear ratios are great for beginners and they do not create the same amount of revolutions with each pedal. These ratios are also used by experts to scale up mountains at a slower speed without tiring you out as much.

• Finding The Right Gear Ratio: Unfortunately, no set number is considered the right ratio for specific riders. Since mtb drivetrain vary and the cassette sizes can also vary, you will need to play around with your drivetrain to find the ideal ratio for your needs. It is best to start small on a flat road and try to find out which gear ratio is the most comfortable. Once you have a basis, you can slowly go up and down with the speeds.

Which Drivetrain Combination Is Best For You?

It is hard to determine the best drivetrain combination since there are so many great ones to look at. However, the standard 21-speed drivetrains are often more reliable for beginners and they do not have the same gears in between that you will need to understand. This will remove some of the complications and allow you to pedal.

However, expert riders might need something more, which means that the 50-speed drivetrains care often better for the versatility they offer. Regardless of your experience, you need to invest some time in understanding the drivetrain. We would recommend the SRAM Eagle Series as one of the best options for experts and beginners.


The mountain bike drivetrain are not that complicated once you have a basic understanding of the components and how they work. However, it is your responsibility to put in the time to look at the information and study these drivetrains. Let us know in the comment section which drivetrain you have for your mountain bike.

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