There’s plenty of discussion around 1x and 2x drivetrains, but this is the REDCHILLI perspective — shaped by real builds, real riders, and the realities of the road.
A transmission choice is felt long before it is noticed. It is there when the road steepens halfway through a winter sportive, when a fast group presses on down a descent, or when a gravel climb asks for one more easier gear. The question of 1x or 2x transmission – which is best is not really about following a trend. It is about giving your riding the right range, rhythm and level of simplicity.
A well-chosen drivetrain should disappear beneath you. The gear arrives when you need it, your cadence feels natural, and your attention stays on the road or trail ahead. There is no universal answer, but there is usually a clear answer for the rider, terrain and purpose of a particular build.
1x or 2x transmission: the essential difference
A 1x transmission uses one chainring at the front and a wide-range cassette at the rear. There is no front derailleur, no front shifter and no need to manage shifts between chainrings. A 2x system uses two chainrings and a front derailleur, paired with a cassette that usually has more closely spaced sprockets.
The distinction sounds simple, but it changes the character of the bike. A 1x system favours clean operation, security and straightforward decision-making. A 2x system gives a broader spread of ratios and smaller jumps between gears, which matters when maintaining a precise cadence at speed.
Neither is automatically lighter in every finished build. Removing a front derailleur and shifter saves components, but a 1x setup often needs a larger, wider-range cassette and rear derailleur. Weight is rarely the deciding factor. The useful question is whether the ratios work for the rides you actually do.
When a 1x transmission makes sense
A 1x drivetrain is particularly at home on gravel, mixed-surface riding and builds intended for uncomplicated all-weather use. With a narrow-wide chainring and clutch-equipped rear derailleur, it offers excellent chain retention over rough ground. There is less hardware around the bottom bracket, more tyre and mud clearance on many frames, and one less mechanism to adjust.
That simplicity has a real riding benefit. On an undulating trail, a rider can shift through the cassette without considering which chainring they are on. There is less chance of an awkward front shift under load and less mental clutter when the surface is changing quickly. For adventure riding, bikepacking and technical gravel, that calm can be more valuable than perfectly even gear steps.
Modern 1x gearing is far more capable than it once was. A 42-tooth chainring with a 10-44 cassette, for example, provides a low gear of just under 1:1 while retaining a 4.2:1 top gear. That can cover a great deal of British gravel riding, especially for a strong rider on sensible tyre sizes.
The compromise comes at either end of the range and in the gaps between ratios. To create a low enough climbing gear without a second chainring, cassette sprockets must make larger jumps. On the road, those jumps can make it harder to settle into a preferred cadence. A rider may find one gear slightly too light and the next slightly too heavy, particularly into a headwind or during a steady threshold effort.
A single front ring also asks for a choice. Fit a smaller chainring and steep climbs become more manageable, but you may spin out on fast descents or in a quick chaingang. Fit a larger one and the bike feels stronger at speed, but the lowest gear may become a poor companion on a loaded gravel climb in Dartmoor or the Lake District.
Why 2x remains the road rider’s benchmark
For most performance road, endurance and fast sportive builds, 2x remains the more complete answer. The two chainrings allow a wider overall range without demanding huge gaps across the cassette. You can have a genuinely useful low gear for long climbs and a high gear that still feels composed when the pace rises.
Consider a compact-style 48/35 chainset with a 10-36 cassette. Its highest ratio is 4.8:1, while its lowest is just under 1:1. That is a similar climbing ratio to the 42 x 44 1x example, but with a substantially taller top gear. More importantly, the cassette can be more tightly spaced, making it easier to make small cadence adjustments during sustained road riding.
This matters more than many riders expect. On a long solo ride, a small change in cadence may be inconsequential. In a group, on a rolling circuit, or during a time-sensitive event, being able to hold your preferred rhythm can save energy. The front shift is an occasional, deliberate change of range; the rear cassette then offers the fine adjustment within that range.
A 2x system does require careful setup. Front derailleur position, cable tension on mechanical systems, chain length and chainline all need attention. Yet on a properly assembled and maintained bike, a modern front shift is fast, controlled and reliable. It should not feel like a compromise in usability.
There is also an efficiency consideration. A 2x drivetrain often allows a straighter chainline across the gears used most frequently on the road. The difference is not always dramatic in real riding, but for riders who spend long hours at steady power, it is another reason a 2x setup remains compelling.
Match the transmission to the riding, not the category
It is tempting to call 1x the gravel option and 2x the road option. That is a useful starting point, not a rule. Some gravel riders need the close cadence control of 2x because they cover long stretches of tarmac, ride fast events or travel with loaded bags. Some road riders genuinely prefer 1x for winter training, rolling terrain and the clean simplicity of a single shifter decision.
The right choice begins with the hardest and fastest moments of your normal rides. Ask whether your limiting concern is climbing low enough, pedalling fast enough downhill, or finding the exact gear to hold a steady effort. Then consider the terrain honestly. A flat local loop, a hilly sportive, Alpine travel and rough moorland tracks place very different demands on the same bike.
Your preferred cadence matters too. Riders who are comfortable allowing their cadence to move around will generally tolerate wider cassette jumps better. Riders who naturally ride at a consistent cadence, or who compete on the road, are more likely to appreciate the refinement of 2x.
Wheel and tyre choice can alter the answer. Larger gravel tyres reduce the effective rollout of each gear slightly, while fast road tyres and deep-section wheels can make a taller top ratio more relevant. A transmission is never an isolated specification. It should sit alongside frame purpose, tyre clearance, wheel choice, riding position and the rider’s power.
The better question to ask before choosing
Rather than asking whether 1x is newer or whether 2x is more traditional, ask what you do not want the bike to make you compromise on. If you want a clean, dependable drivetrain for rough tracks and varied conditions, 1x may be exactly right. If your priority is broad range and smooth cadence control across fast road miles and steep climbs, 2x is usually the stronger choice.
There are practical details worth settling before the build is finalised: the chainring size, cassette range, derailleur capacity and whether a future change in fitness or riding ambitions should be accommodated. A 1x system can often be tuned with a different chainring. A 2x build can be tailored with different chainring pairings and cassette sizes. The best specification leaves room for the rider you are becoming, not just the rider you are today.
At Redchilli, this is why drivetrain choice is considered alongside fit and intended use rather than selected from a standard package. The aim is not to make a bike look current on a specification sheet. It is to make every ratio feel intentional when the ride gets demanding.
The best transmission is the one that lets you climb without dread, ride at speed without running out of gear, and settle into your own rhythm without thinking about the mechanics beneath you. Get that right, and the bike feels less like a collection of parts and more like a trusted extension of your effort.
Choose the transmission that supports your ride
The best drivetrain is the one that lets you climb without strain, hold speed without searching for the right gear, and settle into a rhythm that feels natural on your roads. When the transmission matches your terrain, your cadence and your intent, the bike feels calmer, faster and more purposeful — not because of the number of chainrings, but because every ratio feels like it belongs to your ride.
If you’d like help choosing between 1x and 2x for your build, your terrain and your riding style, then Redchilli Bikes are always happy to advise and ensure every gear on your bike feels intentional.