Settling on the type of drivetrain will probably be one of your first dilemmas when it comes to buying a gravel bike. So why did manufacturers suddenly start putting just one chainring at the front, and does this make any sense when it comes to regular riding?
It's hard to say really, and again, like some mantra, the words that spring to mind are "nothing is everything". The 1x11 drivetrain is already standard in MTB and CX. So how does a gravel bike relate to this type of drivetrain then?
The 1x11 drivetrain - where did it all begin?
The first bicycle company to ditch the front derailleur and go for a 1x11 drivetrain was SRAM.
Beginning in 2012, their solution first spread to the world of MTB until seamlessly moving into cross-country races and finally landing on adventure and gravel bikes.
A gravel bike – what is it, anyway?
To somehow address our problem, we should first briefly characterize what gravel bikes are, and, even more importantly, take into consideration their purpose.
Gravel bike, as the name suggests, is a type of bike designed to ride on gravel and loose surfaces. For many of us, it's a universal bike, a machine that's suitable for anything from a long expedition to a road ride, or just a quick trip to the store for a couple of bread rolls.
Technically, it's a mutation of a road endurance bike, with solutions taken from cyclocross and MTB. Gravel bikes have wide drop bars that flare outwards (for stability in tough terrain), disc brakes (high braking force is required when riding with luggage), and many bosses for mounting fenders, bikepacking bags and panniers.
The geometry is a variation on the road endurance bike - a tall headtube for comfort on long distances, relaxed frame angles, a long wheelbase, and a low bottom bracket for stable, and reliable handling with heavy loads and at speed in difficult terrain.
The gravel bike is, therefore, a machine that is, on the one hand, supposed to be very versatile in terms of the terrain it covers, and, on the other hand, simple, resistant to dirt and damage. And most importantly, it must be very, very comfortable. Let's now tell you in a few words about the drivetrains we can choose from.
Characteristics of a drivetrain with one chainring
SRAM has changed the perception of the drivetrain with a single chainring up front by introducing narrow-wide chainrings, now commonly used on bikes such as gravel, cyclocross, and MTB.
What exactly is this solution? Well, with an ordinary 2-chainring crankset, the teeth of the sprockets are the same width to fit into the chain. But, with narrow-wide chainrings, the teeth are alternately wider and narrower to fit exactly into the outer and inner chain links, which are different widths.
Additionally, the chainring has special grooves designed for chain retention, keeping it firmly in place. So we don't have to worry about our chain falling off while riding, nor do we need a front derailleur or a chain guide.
The narrow-wide system coupled with the rear derailleur, which has a so-called clutch for better chain tension, gives us optimal security and the confidence that the chain is going to stay in place, without generating any additional resistance.
On the long trips, due to its simplicity, a 1x11 drivetrain can be a considerable advantage, and it's also just as great for rides in tougher terrain.
Characteristics of a 2x11 drivetrain
Drivetrains with several chainrings have been in use for a long time now. Most notably, they offer excellent versatility due to their greater range compared to 1x11 drivetrains.
Drivetrains with 3 sprockets at the front have long since come out of sporting use. They weighed more, and gear shifting wasn't really ideal. The 2x11 has eliminated some of these problems.
A drivetrain with several chainrings allows for large, rapid gear shifting through the front derailleur and fine shifting through the rear derailleur.
For sure, a solution like this will be really beneficial when it comes to gravel riding in the mountains. But still, we can't use all the gears because of a bad chain line at extreme gears, meaning there’s a greater risk of the chain falling off, and we also have an extra derailleur to adjust.
1x11 versus 2x11 on a gravel bike - advantages and disadvantages
- Simplicity - the 1x11 drivetrain has a single shifter and no front derailleur, so there's far much less equipment to adjust, and thus becomes a bigger time-saver. There are also fewer parts that are likely to fail.
- We can use every gear combination - unlike the 2x11, where some gears overlap. A 1x11 drivetrain utilizes all the gears.
- Chain drop - With a 1x11 this isn't an issue. Narrow-wide chainrings and a clutch derailleur provide maximum security.
- Chain line - you don't have to think about if you are in the right gear. With 1x11, each one is functional.
- Lighter weight - getting rid of the derailleur, the shifter, and the small front chainring all add to a considerable saving in weight.
- Noise - due to the clutch in the derailleur, the chain makes much less noise when riding off-road.
- Cleaning - one chainring at the front makes it very easy to clean the crankset and access its recesses.
- Cost - after wear and tear, we have 1 chainring to replace instead of 2.
- Bigger gaps - to ensure a good range of gears, the gaps between the cog sizes in the cassette have to be larger, so it’s going to be tougher to stick to our optimal cadence. For some of us, this isn’t going to be a problem, but for others, it might be a big one.
- Smaller gear range - in some cases with 1x11 drivetrains, especially with stock configurations, we have access to a smaller range of gears than we would need on a long bikepacking trip. The Loca Bikes gravel bikes have cassettes with a wide gear range, so you can easily take on most of the climbs.
- Chain line - not every gear combination is ideal, so this can lead to faster wear and tear on the drivetrain (but you'd have to be constantly riding in the extreme gears on the cassette)
- Spinning backward - at very low gears, when turning the pedals backward, the chain can sometimes jump onto another sprocket. However, this isn’t a problem with just regular riding.
Should I go for a 1x11 or 2x11 drivetrain?
It depends on your preferences and what routes you'll be taking your gravel bike on. There's not a solution for everything. The main advantage of a drivetrain with two chainrings is the greater range of gears.
So if you are intending to travel with a heavy load over very varied terrain in terms of altitude, with a 1x11 drive, you may sometimes lack the low gears you need.
This problem is reduced to some extent by wide-range cassettes and, of course, 1x12 drivetrains, which already provide good gear ratios suitable for every climb.
The lack of a front derailleur can sometimes be bothersome if you don't like to shift through the entire cassette before getting to the desired gear. A 2x11 will, on the other hand, allow you to make quick, big gear changes.
The advantage of the 1x11 drive is its simplicity and reliability off-road. Fewer elements leave us with better weight, and the narrow-wide chainrings and clutch make the problem of chain drop a thing of the past.
If you know what kind of terrain you'll be riding on, or if you're simply certain that you won't have to conquer flat prairies (problem with wide gear gaps), a 1x11 drivetrain may be for you.
By installing a wide-range cassette, in most cases, you eliminate the problem of having a lack of gear ratios, and if you're a fan of simplicity, with a clear conscience, you can safely go for a single chainring drivetrain for your gravel bike - even if you're intending to go to the mountains.
On our website in addition to fixed gear and city bikes, you can also find the latest range of Loca Bikes gravel bikes. Write to us, we'll happily answer any questions that you have, and what’s more, we'll put a nice bike together for you.