How Mountain Bike Gears Work

Last Updated on December 24, 2021

Mountain bikes move thanks to their drivetrain. This drivetrain is also commonly known as gear. Many are into mountain biking, but most still don’t know how gears work and how the chainring and cassette sprockets affect your pedaling efficiency.

That’s what this article is about. Because here, we’ll show you how these gears work and how you can use them to their full potential. Not only do these make your bike move, but they can also make you go faster and keep you safer when out on the trails.

What are mountain bike gears?

Mountain bike gears can be referred to as speeds. A mountain bike that has 10 gears is a 10-speed bike. Bikes usually have 27 speeds. However, more modern and expensive bikes now only have 11 or 12 speeds because of their 1x drivetrain.

The lower the numbers are, the lower gears they are. Higher numbers then mean higher gears. The first gear is the lowest gear, while the last gear on top of the cassette is the highest gear.

Meanwhile, shifting means going from one gear to another gear. You shift gears by simply pressing the shifter lever using your thumb or pointer finger. Every kind of bike has its own shifting mechanism.

City bikes usually have twist grips where you just twist the sides of the grips for it to change gear. Meanwhile, mountain bikes have a shifter lever. SRAM has a different mechanism from Shimano because you can shift to the lower or higher gear by just using your thumb with SRAM.

Meanwhile, you use your thumb to shift to a higher gear with Shimano, and then your pointer to shift to a lower gear. Shimano, however, is also starting to go into one-finger-only shifting with its higher-end models to keep up with SRAM’s convenience.

How to know the number of bike gears?

You can know the number of gears your bike has by adding up the cogs at the back and then multiplying it with the number of chainrings upfront.

Most budget bikes are either 21-speed or 24-speed because they have 3×7 or 3×8 setups, respectively.

Meanwhile, most modern and mid-end cross-country bikes have a 2x setup. These 2x setups mean that they have two chainrings. These also are usually paired with 10 or 11 cassette cogs at the back.

How do mountain bike gears work?

how do mountain bike gears work

Mountain bikes usually have a 2x or 3x drivetrain setup. This means that they have either two or three chainrings. The three chainrings are connected to the left shifter.

When you press this left shifter to the lower gear, the front derailleur brings the chain down and makes it heavier for you to pedal. If you press it to a higher gear, the derailleur then brings the chain up and makes it lighter to pedal.

On the other hand, there is also the right shifter. This shifter controls the cog cassettes at the back, which is where 7, 9, or up to 12 cogs or gears are in.

Most budget bikes have an indicator on their shifters which tells what gear they are in. However, high-end drivetrains don’t have an indicator. Why? Well, because you don’t really need them! You don’t need to look at the number of what gear you’re in.

Instead, you just feel the current gear you have. Knowing what gear you are in is not really important. It’s about the feel of the gears that counts.

1x versus 2x Drivetrains

This has to do with the number of cogs most mid-end to high-end drivetrains have now. Shimano and SRAM’s mid-end range has already 11 cogs. While their high-end options have 12 cogs.

This means that they are already 11-speed and 12-speed gears, just like the SRAM XX1. You might think that’s just too little. Well, that’s where you’re wrong.

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These are enough because having 2 or 3 chainrings would just make your bike heavier. And their speed adjustments are just redundant. Why would you rely on your chainrings, if you already have enough cogs at the back?

Not only does a 1x drivetrain shed off a considerable amount of weight from your bike. But it’s also easier to maintain. You don’t have to constantly adjust the front derailleur because you won’t have any!

You’re also safer with 1x drivetrains because you’re less likely to accidentally hit the sharp chain rings upfront or the pointed front derailleur.

What shifter to use?

You need to shift to a lower gear if you’re going downhill while maintaining the right gear combinations. Meanwhile, shift to a higher gear if you’re riding uphills.

Low gear means that your rear cassette brings your chain to the small cogs. This makes you go faster in the right gear ratio when shifting gears, but the pedaling becomes harder and heavier. On the other hand, a high gear range means your chain goes to the larger cogs which are softer to pedal. Learn how to play with multiple gears from the easiest gear to the lower gear which are harder.

Tips for Proper Gear Shifting

Anticipate the trail

Shift to a softer gear if you are approaching a climb and anticipate how many gears you’ll shift and pedal stroke to do when approaching a steep hill. Don’t stop or slow down. Instead, immediately shift to the higher gear. Gently relax the amount of pressure you put on your pedals so you don’t grind too many gears when riding on trails.

Then shift your rear derailleur or rear cog to a lower and harder gear if you are approaching a downhill descent. You’ll find this near your rear wheel. It’s safe to always be on a lower gear so that your rear gears aren’t hyperextended and are less likely to hit something.

Use an easier gear if confused

It might seem nice to go hard on your bicycle gears because you go faster. But don’t force yourself if you’re still new to mountain biking.

Sometimes, it’s nice to have your rear cassette on heavier gear because you have less pedaling. But that will suck out your energy faster especially if you are approaching a climb. Keep in mind that you should maintain the highest pedaling speed you are most comfortable with for an extended amount of time.


Learning how the gears of mountain bikes work is important to have a safer and faster ride. You don’t just ride your bike and hit the pedals to move. You need to be at the right pace and speed. And that’s just what gears, or more specifically speaking, drivetrains do.


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