Oh yeah, gravel is where it’s at! Gravel biking gives you that sense of adventure, tough workout and tests your skills. Bike manufacturers are quickly hopping on the bandwagon with all kinds of fresh new gravel bikes, including bikes with gravel-specific drivetrains.
Mountain bikes have long touted the benefits of a 1x drivetrain, but now the trend is seeping into other cycling disciplines, such as cyclocross, road riding, and gravel. There are many pros and cons to riding a 1x gravel bike, so how do you decide if it’s right for you?
A gravel bike with a 1x drivetrain will be lighter. It will reduce chain slap and chain drop and reduce shifting complexity. But there are times when a 2x drivetrain is better, too. To decide which one is better for your bike, you need to examine the pros and cons of both 1x and 2x drivetrains.
In this article, we’ll take a deeper look at the pros and cons of using a 1x drivetrain on your gravel bike and compare it to a 2x drivetrain. But, first, let’s look at the difference between a 1x and a 2x drivetrain.
What’s the Difference Between 2x and 1x Drivetrains on a Gravel Bike?
What is a Drivetrain?
The simplest way to think of the drivetrain on your bike is to picture all of the parts that make your bike go. (Source)
It starts with the pedals. When you push down on the pedals, the cranks turn the chainring, pulling the chain through the system.
Next, the chain will turn the rear cassette, which turns the wheel.
Along with a few others, all of the parts propel your bike forward.
Standard 2x Drive Train
2x (usually pronounced two by) signifies that you have two chainrings in the front of your bike’s drivetrain: a large chainring and a small chainring.
Some road bikes will have 3, but generally, bikes just have two. You’ll also have a variety of cogs in the rear.
You’ll use the shift levers on the handlebars (or buttons, if you have Di2) to change the chainrings or the cogs. The combinations you choose will make it harder or easier to pedal.
Let’s take a look at the canyon Grizl CF SLX 8 Di2.
This gravel/adventure bike has two chainrings in the front: a 48/31T. Its cassette is an 11-34.
This combination gives you lots of gears to choose from for steep ascents and speedy descents, as well as rough flat terrain. Your easiest gear ratio is a .9. This small number means that your wheel rotates 9/10 of a turn for every turn of the pedals; that’s a great climbing gear!
The hardest gear is a 4.36 – that means your wheel goes around 4.3 times for every turn of the pedals.
That’s a hard gear to push, but it will move the bike pretty far! Great for when you need to sprint or pedal on the descent.
A 1x drivetrain means you only have 1 set of chainrings in the front, rather than 2.
So the type of gearing you have will depend on the combination of chainring and cassette that you have on your bike.
For example, the Canyon Grizl CF SL 7 1by has a 40t chainring in the front with an 11/42 cassette in the back. This combination gives you a range of .95 for the easiest gear (great for hills) and 3.6 (great for flats).
The compromise here is that the gears are a little further apart, which means you’ll have to adjust your cadence more rather than changing the gears to fit your cadence.
If you know the type of terrain you will be riding, you can change out your cassette and chainring for something a little different (within limits, of course).
As long as it fits on the bike, you could use a smaller chainring to make hill climbing easier or a larger one if you’ll be riding a lot of flats.
Now that you can understand the difference between a 1x and a 2x drivetrain on a gravel bike let’s look at how a 1x drivetrain might be better for your needs.
Pros of a 1x Drivetrain On a Gravel Bike
Weight weenie jokes aside, and you might prefer the weight-saving benefits of a 1x drivetrain.
First, you’ll save about 200 grams by not having a front derailleur.
This amount may not sound like much, but when you’re trying to shave as much weight as possible for these steep hill climbs, every little bit matters!
Fewer Chain Drops
One of my favorite aspects of a 1x drivetrain is that it seems to have less chance of dropping your chain.
Even as an experienced rider, I still get occasional chain drops. It happens if I shift to my smallest front chainring and smallest cog in the back.
Yes, crossing the chain is a no-no, but sometimes it just happens. And it usually sends my chain right where I don’t want it to go – off the chainring.
I appreciate that this doesn’t happen on. My 1x chain is less likely to bounce off the chainring, as well, even when you’re hitting some pretty rough terrain.
And the chain is less likely to get jammed up between two gears.
Another benefit that I love with my 1x bike is the simplified shifting.
Simplified shifting is great if you don’t want to think much about how and when you shift or if you are a beginner and find shifting a mysterious part of bike riding.
Basically, you shift to a harder gear when the terrain is easy and into an easier gear when the terrain is hard.
But with a 2x drivetrain, shifting is a little more complicated.
With a 2x, you have a few gears on each chainring that are duplicated by the other one. Using these gears will put a lot of tension on the chain, so it’s best to avoid them (and they can cause your chain to drop, as well).
When you shift the chainring, you almost always need to shift the cassette to prevent this.
You might hear this called Alpine shifting. When you shift up one gear on the chainring, you shift down two on the cassette.
And when you shift down on the chainring, you shift up to one the cassette. It keeps your cadence smooth and your chain under the correct tension, but it is definitely a little more complicated than shifting with a 1x.
More Clearance For Bigger Tires
Without sacrificing responsiveness, a 1x drivetrain will give you more clearance for wider tires.
If you want a snappy, more responsive ride with bigger tires, then you’ll wish to a 1x.
You need a longer chainstay to fit larger tires on a 2x drivetrain. But a longer chainstay makes the bike a little slower, while shorter chainstays, made possible by removing that front derailleur, will make the bike much more responsive.
Better Riding In Bad Weather
If you do a lot of riding in bad weather or muddy conditions, you might want a 1x drivetrain. You won’t have a front derailleur to pick up extra mud and dirt, so your bike will function better when the weather is bad.
It is definitely worth considering if you ride your bike in wet, muddy conditions a lot.
Fewer Parts To Break
The fewer the moving parts, the less you have to worry about them breaking down. And of course, less breakdown means less time in the bike shop and more time on the road or trail, as the case may be.
There are plenty of reasons to use a 1x gearing, but there are also some reasons you might not want to use it, as well.
Cons of a 1x Drivetrain On a Gravel Bike
Restricted Gear Range
A 1x drivetrain will limit your gearing choices. Of course, you have options, but you’ll have fewer options than if you have a typical 2x drivetrain.
For example, if you’re using a 40t chainring in the front and an 11-34 cassette in the back, you’ll be limited to those mid-range gears as I have on my cyclocross bike.
If you aren’t riding anything too steep or too fast, you’ll probably be ok with a setup like this. But if you’re trying to keep up high speeds on a flat paved road, you might find yourself falling off the back.
You would need the wider range of gearing that you can get from a 2x drivetrain to fix this. However, it’ll give you more easy gears and more hard gears without sacrificing your cadence.
On the other hand, if you know you’ll need easy gears for climbing, you could choose a 1x drivetrain with a wider range of gears in the back.
For example, you could have a 42t chainring in the front and an 11/42t cassette in the back. This combination of gears will give you a nice wide range of gears, but this compromise here will be on your cadence.
Less Efficient Cadence
Unfortunately, if you have a 1x drivetrain, your cadence might suffer.
If your gearing choice is suitable for, say, climbs, you’ll have trouble on the flats. You’ll need a very fast cadence to keep up if you’re riding with friends who are on 2x setups.
The high cadence might tire you out very quickly.
On the other hand, if you use a gearing choice that suits speed more than climbs, you’ll suffer going uphills.
You’ll either have a very low cadence to grind your way to the top, or you might even have to stop pedaling and hike your bike up the steeper hills.
Less Speed On The Flats
If you are riding on flats, your speed might suffer because you don’t have enough hard gears to keep up.
Less Efficient Drivetrain
Surprisingly, 1x drivetrains are not really as efficient as 2x drivetrains are. (Source)
This inefficiency happens because the angle of the chain from the chainring to the cassette is greater.
In turn, the angle causes more friction on the chain, making it move less efficiently. As a result, it’ll take a little more work to move the bike.
More Difficulty Racing On Flats And Hills
If you’re racing gravel, you might need a 2x set up to keep your speed on both flats and hills.
Although a 1x will save you weight (and weight on climbs equals speed), it might not be enough of a benefit over the length of a gravel race. So you might want the gearing range of a 2x set up to help you race on both flats and hills.
Some manufacturers (like Obed) offer the same gravel bikes with both 1x and 2x setups.
Because gearing choice is very personal and is based on the type of rider you are, the type of ride you’ll be doing, and even your budget.
If you are coming from a mountain bike background, you’re probably already used to a 1x setup, so this would be an easy transition.
But, of course, if you’re coming from a roadie background, it might feel more natural to go with a 2x anyway.
Since gravel is typically slower than the road, you may not be worried about having the gears go fast. If that’s the case, a 1x might be just the thing because it is lighter and simpler.
If you are riding for fun, you might love the simplicity of a 1x setup.
And if you’re going to be racing at higher speeds or climbing as well as hitting the flats, you might prefer to have the extra gear range you can find on a 2x setup.
I love my 1x setup for short gravel rides that might cover a little single track and some minor climbs.
On the other hand, I’ll choose my 2x setup for longer days when I’m hauling lots of gear along or hitting long steep climbs. The beauty of gravel gearing is that you get to choose whichever suits you best!