1x12 mountain bike drivetrain: How to choose the right setup for your riding

12-speed drivetrains have taken over modern mountain biking. If this technology is new to you, or you would like to understand why it is so popular, read on. This short guide will explain what they are, how they are different from the kind of systems used in the past and why they have some really good benefits for riders.

A 1x12 mountain bike drivetrain refers to how a mountain bike’s gears are arranged. The one means it has a single chainring mounted on the crank, and the 12 means it has 12 cogs on the cassette on the rear wheel. This gives the rider 12 gears to use as they ride, going from the biggest cog on the cassette for an easy climbing gear to the smallest cog, which gives a hard gear for very fast riding.

With a 1x12 drivetrain, there is only one chainring on the crank, so all the shifting happens on the cassette mounted on the rear wheel of the bike. These systems only have one shifter, mounted on the right-hand side of the handlebars. Using this, you use the derailleur to push the chain up and down the cassette, selecting a gear that suits the riding situation you are in.

1x, 2x and 3x drivetrains all refer to the number of chainrings mounted on a bike’s crank. In the past, 2x and 3x drivetrains were the most popular, while today almost all modern mountain bikes come with a 1x drivetrain. By using two or three chainrings and a front derailleur, riders could have a wide range of gears to suit different situations. The downside is that this meant riders needed to have two shifters, one for the front and one for the rear derailleur. When riding with a 2x or 3x system, you needed to think about the combination of chainring and cassette to find the right gear, while with a 1x system, you only need to think about where you are on the cassette and operating one shifter, making gear changes much simpler.  

The simplest answer to this is obvious - a 12-speed system has one extra cog on the cassette compared to an 11-speed system. But there is also a bigger difference. Many 11-speed drivetrains were designed around two or three chainrings at the crank and used a much smaller cassette. To make sure that riders still had a good range of gears for different situations, 12-speed cassettes have a much wider range of gears - the smallest cogs are smaller than on an 11-speed cassette, and the biggest cogs are much bigger. This means that even though they only have one chainring, riders still have the same kind of range of gears as a 2x or 3x system. This shift to a single chainring also allowed manufacturers to build chain retention into the derailleurs.

Modern 1x drivetrains all have chain retention systems built into them. These work in two parts. Firstly, the derailleur has what is called a clutch mechanism built into it. This stops the derailleur cage from swinging forward on rough terrain, reducing the chance of it skipping off the cassette or chainring. The second is in the shape of teeth on the chainring. They use a special profile that makes it harder for the chain to skip off the teeth, but would also make it hard for the chain to be shifted sideways onto another chainring.

1x12 mountain bike drivetrains originated in mountain bike enduro racing. In this discipline, racers need to cover long distances, but are only timed on the downhill sections of the race course. They found that with 2x and 3x drivetrains, with their front derailleurs and multiple chainrings, they were dropping chains when things got rough. To solve this, they began using downhill-style chainguides to keep their chains on. This meant they were unable to use 2x and 3x setups as the guide replaced the front derailleur.

In the beginning, enduro riders used modified 10 and 11-speed drivetrains for racing. As the sport grew, drivetrain manufacturers began creating enduro-specific drivetrains with single chainrings, large, wide-range cassettes and built-in chain retention. Soon, they began to realise that there were many benefits to this kind of drivetrain system and the technology fed through to all disciplines of mountain biking.

So why did 1x12 become the industry standard? A quick look through the pros and cons of 1x vs 2x and 3x tells a clear tale:

As you can see, there are a lot of upsides to 1x drivetrains, without too many drawbacks.

There can be a few different reasons for choosing a 1x12 mountain bike drivetrain, depending on what style of riding you prefer.

Modern cross-country bikes, like our Lux World Cup and Exceed models, all come with 1x12 drivetrains. For this style of riding and racing, the weight saving cannot be ignored. By ditching the front shifter, derailleur and second and third chainrings, it can save a noticeable amount of weight compared to a 2x or 3x setup. The chain retention benefits should not be ignored either. While dropped chains are less common in XC than in enduro racing, in intense head-to-head racing, nobody wants to be left behind their competitors while they try to fight a greasy chain back onto their drivetrain.  

We think simplicity and affordability are the best arguments for using a 1x drivetrain for trail riding. This is why all of our Spectral and Neuron models now come with 1x drivetrains. Using a single shifter to manage your gears out on the trail and having a single derailleur to maintain is the best choice for trail riders. Throw in the fact that 1x drivetrains with fewer components cost less, meaning we can offer these bikes at more affordable price points, and we think the case for 1x for trail riding is undeniable.

With 1x drivetrains originating from enduro racing, it should be no surprise that our Torque enduro bike is equipped with a 1x drivetrain. One of the overlooked advantages of a modern 1x12 mountain bike drivetrain is that the tiny, 10t cog on a modern 12-speed cassette means that you can run a smaller chainring than was possible in the past - reducing the chance of hitting it against obstacles on the trail and derailing your run.

The one area of mountain biking where 1x12 drivetrains do not rule the roost is in downhill racing. Quite simply, for downhill racing, where you are not going to ride back up the hill, there is no need for so many gears, so it is better to save some weight. This is why the major manufacturers produce downhill-specific groupsets with fewer gears, and our Sender downhill race bike comes with a 7-speed drivetrain. 

Some people spend a lot of time online arguing over whether Shimano or SRAM make better drivetrains. The truth is that there are small differences between the two brands in things like shifting feel, chain retention and ergonomics, but both manufacturers make great components. There are two factors that we think make the most sense when choosing between the two. Firstly, what drivetrain do you have on your bike now? for instance, you cannot use a Shimano shifter with a SRAM derailleur. Both companies design their components to work in an ecosystem of their components, so unless you are thinking of changing the whole drivetrain, it is best to stay with the manufacturer you already use. After that, it is simply a question of what you can find that best suits your budget.

If you want to go deeper into the topic, check out our MTB groupset guide, where we break down the key differences and help you choose the right setup for your riding style.

This is entirely a budget decision. As great as electronic drivetrains are, there is no escaping the fact that they cost a lot of money. They offer some small advantages in terms of ease of installation, shifting speed and cool robot noises, but it is in the fine details. At the end of the day, whether you have a mechanical or electronic drivetrain is unlikely to change the size of your smile at the end of a ride.

One of the benefits of a 1x12 drivetrain is that there are fewer choices to make, so less chance of getting it wrong. You need to check the compatibility of your rear wheel for 1x12 because it will need a Shimano Microspline or SRAM XD driver body to fit a 12-speed cassette. You will also need to check your derailleur hanger because the latest generations of 12-speed derailleurs require a specific type of dropout, usually a SRAM UDH. If you are looking to fit a larger chainring, you will also need to check the clearance for your frame, because many modern mountain bikes are designed around smaller chainrings. After that, there should be no reason you cannot install a 1x12 drivetrain on your mountain bike.

There are two areas you need to consider for setup, and they are the size of the chainring and the cassette. The smaller the chainring you buy, the easier your gearing will be, while this is reversed for the cassette - a bigger cassette means an easier gear. If you are not confident of your strength, it is probably best to start with a small chainring of 28 or 30 teeth and a big cassette with 51 or 52 teeth for the easy gear. This means you will have a nice, comfortable gear for climbing, but you might run out of gears on the way back down, which sucks way less than running out of gears on the way up.

With only one derailleur to look after, 1x12 drivetrains are much simpler to maintain than older 2x and 3x systems. Modern chains have a pretty good lifespan, but it is worth keeping an eye on how quickly your chain is wearing and whether the teeth on the chainring and cassette are in good condition. To maximise the life of your drivetrain components, you should keep the chain clean and well-greased. If you hit your derailleur out on the trail, you should always check afterwards to make sure your drivetrain is still correctly aligned.

Unless downhill is your passion, we think 1x12 drivetrains are the best option for mountain bikers of all levels and riding styles. They are simple, more affordable and offer all the gearing most mountain bikers need to have a great ride. This is why all of our mountain bikes today come with 1x drivetrains, from advanced e-MTBs through to affordable hardtails, from cross-country race machines through to enduro trail monsters.  

We hope this guide has helped you shift into a good gear. See you out there on the trails!