Gearing Up for Adventure: 1x vs. 2x Drivetrains

Drivetrains for Bikepacking - Which is Right for You?

You’re two days into a remote bikepacking trip. The sun beats down, your bike is loaded heavily with gear, and ahead lies another brutally steep, loose track snaking up the mountainside. Every stroke is an effort. Your legs burn, your lungs ache, and your mind focuses on just one thing – keeping the cranks turning. In moments like these, proper gearing isn't just about comfort; it's fundamental to moving forward, conserving energy, and maintaining morale.

Choosing the drivetrain that best handles these challenges, along with the rolling miles and fast descents, is one of the most critical decisions when setting up your bikepacking rig.

For years, triple chainring (3x) setups were the standard for touring bikes, offering a massive gear range. But today, the debate primarily centers around two simpler systems: the single front chainring setup, known as "1x" (pronounced "one-by"), and the double front chainring setup, or "2x" ("two-by"). Both have passionate advocates and distinct advantages, especially when viewed through the lens of self-supported, multi-day cycling adventures.

This article aims to cut through the hype and provide a practical comparison of 1x and 2x drivetrains specifically for bikepacking and bike touring. We'll dissect the key differences that matter when you're loaded down and far from the nearest bike shop, examining factors like usable gear range (especially for climbing), mechanical simplicity, trailside reliability, weight implications, and overall cost.

There’s no single drivetrain configuration that reigns supreme for every rider and every route. The perfect setup for tackling the rugged singletrack of the Colorado Trail might differ from what’s ideal for a mixed-surface tour through Europe. Our goal isn't to declare a definitive winner, but to equip you with the understanding needed to choose the system that best fits your bike, your budget, and the adventures you dream about.

II. Understanding the Basics

Before the detailed comparisons, let's quickly clarify what defines these two drivetrain systems and the key components involved. Understanding the fundamental differences makes it easier to grasp the subsequent discussion on performance and suitability for bikepacking.

What is a 1x Drivetrain?

As the name implies, a 1x ("one-by") drivetrain uses only a single chainring mounted to the crankset at the front of the bike. To compensate for the lack of multiple front chainrings and still provide a usable range of gears, 1x systems are paired with a very wide-range cassette at the rear wheel – typically featuring 10, 11, or 12 cogs, with spreads like 11-50 tooth (often abbreviated as 't'), 10-51t, or even 10-52t.

To manage the chain across these large cassettes and prevent it from bouncing off on rough terrain, 1x setups rely on a specialized rear derailleur equipped with a clutch mechanism (which increases tension on the derailleur cage) and often a "narrow-wide" front chainring (with alternating tooth profiles to better grip the chain). The entire system is controlled by a single shifter, usually located on the right side of the handlebars.

What is a 2x Drivetrain?

A 2x ("two-by") drivetrain features two chainrings on the front crankset, typically a larger outer ring and a smaller inner ring. Shifting between these two rings is handled by a front derailleur, which physically pushes the chain side-to-side. Because the front chainrings provide significant jumps in gearing, 2x systems usually employ a cassette with a narrower range and smaller jumps between cogs at the rear (e.g., 11-34t, 11-36t, or perhaps 11-42t).

A standard rear derailleur handles shifting across the rear cassette (though some newer 2x gravel/MTB derailleurs also include clutches), and the system requires two shifters – one on the right for the rear derailleur and one on the left for the front derailleur.

Key Concept: Gear Ratio – Your Climbing Power

The crucial output of these systems is the gear ratio. The number of teeth determines this on the front chainring divided by the number of teeth on the selected rear cassette cog. A lower gear ratio (e.g., using the smallest front chainring and the largest rear cog) makes pedalling easier and is essential for climbing steep hills, especially with a heavy load. A higher gear ratio (largest front ring, smallest rear cog) allows for higher speeds on flats or descents.

When comparing 1x and 2x, we're often most interested in the lowest available gear ratio for climbing power, the total range of ratios available, and how smoothly the steps transition between gears. Metrics like "gear inches" or "metres of development" are standardized ways to compare these ratios directly, regardless of wheel size.

III. Head-to-Head Comparison: Key Factors for Bikepacking

Now that we understand the basic mechanics, let's delve into how 1x and 2x systems stack against each other in the areas that matter most during multi-day, self-supported bikepacking trips.

A. Gear Range & Ratio: The All-Important Climb and Cruise

This is the most critical factor for many bikepackers. Can the system provide a low enough gear to comfortably spin up steep climbs when heavily loaded, while still offering enough top-end speed for flatter sections or paved descents?

• Low-End (Climbing Gear): This is where the pedals feel easiest, essential for winching yourself and your gear uphill. Modern 1x systems, particularly those using MTB components, excel here. A standard 1x setup might use a 30t or 32t front chainring with a massive 10-51t or 10-52t cassette. This yields an incredibly low gear ratio (e.g., 30t front / 51t rear ≈ 0.59). Traditionally, achieving such low gears on 2x systems was harder. Still, modern gravel-specific 2x setups (like Shimano's GRX) or MTB 2x systems offer options like a 46/30t or 48/31t crankset paired with an 11-34t or even an 11-40t cassette. A 30t front / 40t rear combination gives a 0.75 – still low ratio, but not quite the crawling gear achievable on the widest-range 1x setups. Some older or custom 2x setups using sub-compact chainrings (e.g., 42/26t) paired with wider cassettes can also achieve very low gears, rivalling 1x. Verdict: Modern 1x MTB systems generally offer the easiest path to ultra-low climbing gears out of the box, though well-chosen 2x setups can get very close.