MTB Maintenance

Your Mountain Bike Gear Options Explained

1 ring, 2 ring, 3 ring... what?

Decades ago the majority of cyclists were riding a fixed gear bike for all terrains, inclines and everything in between.

Although there are some hardcore riders still rocking a fixed gear, a vast majority of us take full advantage of newer technology that allows us to use a variety of gears to assist our cycling performance.

Bicycles for all disciplines have advanced quickly in the past 30 years, and with such great leaps forward, it’s sometimes difficult to keep up with the times. One of the biggest developments has been the drive-train, with gears that allow you adjust the effort needed to cycle various inclines.

We attempt to unravel the oily complex mechanism of chains, sprockets and derailers so you can better understand your gears for an efficient ride and optimum performance.

Why Do We Need Gears?

For most mountain bikers, maybe not so much the downhillers, gears are essential to carry you up that climb, roll over that technical terrain and help balance your pedalling power.

With most physical activities, you are your only limitation. You can only get so much out of your muscles, lungs and pain threshold, but having a variety of gears help compensate for your weaknesses. Pedal power is determined by the force used to turn the pedals, and the speed at which you pedal as well.

Being efficient with how you use your energy is key to most athletes success, especially cross-country racers. Forcing a harder gear, or spinning on a low gear quickly gives way to muscle fatigue. So being able to set the right gear for your skill, the terrain and incline, is important.

What makes the Drive-Train… Drive?

In order to understand gears, combinations and ratios, we need to first understand the complex drive-train mechanism:

Cassette and Derailer

CASSETTE – The cassette sits on the rear wheel, mounted to the hub. It’s compiled from a number of sprockets, varying in size in order to provide a range of gear options. A wide range would be something similar to an 11 tooth sprocket, up to 36 tooth sproket.

Chainset: Cranks, Chain rings

CHAINSET – The chain set sits in front of the drive-train, and is made up of the cranks and the chain rings. A bike can be equipped with 1 to 3 chain rings, depending on your riding style and purpose.

A Derailer with its spring and pulley construction

DERAILER (REAR MECH) – The derailer hangs off the back of the drive-train and is responsible for shifting the chain from one sprocket to the next. More than this, the derailer is important for keeping the tension on the chain when shifting through gears.

FRONT DERAILER – This works in the same way as a rear derailer for shifting the chain from one ring to the next, however it’s not necessary to adjust the tension. These are only applicable for bikes that have 2 or 3 chain rings in the front of the chain set.

Gear Levers

SHIFTERS – These levers sit on the handlebars as part of the bike’s cockpit. They are cable operated to pull on the rear and front derailers with a ratchet and lever system.

Combinations and Ratios

Having the right gear set up on your bike will help you to pedal with efficiency. A number of variables need to be considered before splashing out on a new chain ring, or stripping down you current drive-train.

The gear ratio can be calculated by the gear you’re in using the number of teeth on the front chain ring, and the number of teeth on the rear sprocket: a 32 tooth chain ring with a 16 tooth sprocket gives you a 32:16 ratio, or 2:1. This measurement reflects the number of wheel revolutions that are given per pedal cycle. So in the example above, with a 2:1 gear ratio, one full rotation of the pedals will result in 2 full revolutions of the wheels.

Even the wheel size of your bike will affect your gear set-up. A comfortable pedal power on a 26″ wheeled bike will feel considerably easier than the same gear ratio on a 29er.


Riding style plays an important part in setting up your gear range. If you’re a downhill mosher with a big rig bike, then it’s unlikely you’ll be doing any real climbing. For this reason, many downhill bikes will have a single chain ring in the front, between 32T – 36Tin size, and a limited cassette in the rear, usually between 7 -10 gears. A typical cassette will have a range of sprockets from 12T – 25T, or 11T – 36T.

More and more downhill bikes are beginning to favour the new standard of 27.5″ (650b) wheel sizes which needs to be considered when selecting your gear ratios.

Cross Country

However, if you do long distance cross-country riding, you’ll need a wider range of gears, a 2 or 3 chain ring set up would be advantageous to ensure you power through those climbs, and descend quickly on the other side. A common triple ring arrangement is: 42 – 32- 22 with an 8 or 9 speed cassette in the rear. Typically a range of 12T – 32T, or 11T – 34T.

This is considering that a majority or cross-country riders prefer a 29″ wheel-size for their bike. Having a wide range of gears available offer greater clearance, and variety for the rider to find the right gear for them.

All Mountain

Since the introduction of the 11 speed cassette, many of the newer mountain bikes that are hitting the market have a 1×11 drive-train already set up. This will usually include a single chain ring in the front, ranging from 30T – 34T, and a 10 or 11 speed cassette in the rear. Typically 10T – 42T in range.

The benefits of having a 1x drive-train is that is saves on weight by not having the front shifter, front mech, additional chain ring. It adds more simplicity for maintenance also.

Getting your gear ratios and combinations set-up correctly requires some trial and error to find the right fit for you, taking into consideration variables such as riding style, discipline and wheel size.

Ratios are tricky to get right, but there are calculators and YouTube tutorials online to help you out with the maths ratios, if you get a little stuck.

Once you find a good range of gears for you, you’ll find your rides more comfortable and fun.

You may also enjoy:

Buying Guide: Full-Suspension MTB

Buying Guide: Hardtail MTB

How to set up your MTB Suspension


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