Whenever the topic of 1x versus 2x drivetrains for bikepacking comes up, the conversation gets animated. Like hydraulic vs mechanical or clipless vs flat, it’s one of those issues that tends to inspire debate. Especially if you’ve been riding for a long time on older drivetrains, you may be suspicious of the current 1x craze.
I get it. If you’re used to 2x or even triple chainrings, switching to a single chainring bike can inspire fear: fear of making the wrong decision about an expensive and critical set of components. Or – even worse – fear of being left in the dust by your riding partners if your gearing isn’t right for the terrain.
Recently I acquired a beautiful new bike, my Chumba Stella Ti. She’s a custom build, which means I
have to take responsibility for got to choose all the drivetrain components. Coming from a Salsa Fargo with 2×10 gearing, and before that a 3×10 Surly Long Haul Trucker, I initially couldn’t wrap my head around bikepacking with a single chainring. Surely I would miss all those other gears?
Eventually I took the 1x drivetrain leap. After deep-diving into gear ratios and ranges and talking with the folks at Chumba, I finally came to the understanding that a modern 1×12 drivetrain would probably be better for trail riding, and could be equally good for gravel and doubletrack. Still, I was nervous when taking Stella for her first ride. Would I like the new setup in practice?
1x drivetrains have been mainstream for a few years now, so experienced riders are increasingly faced with making the switch as we consider new bikes. I’m a little late to the party, but I can’t be the only one who was riding an older drivetrain until recently. If you’re thinking about a 1x but want to know more before making the switch, I hope this post will help you navigate the decision.
Who Am I?
I’m a recreational rider who enjoys leisurely touring and bikepacking, as well as bikepack “racing” at my own pace. I usually log a few thousand loaded miles each year, a majority in the US but I’ve had the privilege of traveling by bike on five different continents. Gravel and dirt roads of varying quality are my sweet spot, but I’m making an effort to get better at singletrack and I’ll ride pavement as long as it’s safe.
In the last four months I’ve put about 1300 loaded bikepacking miles on Stella with her Shimano SLX 1×12 drivetrain: roughly 700 miles of gravel and dirt roads, 300 miles of singletrack, and 300 miles of pavement. You can get a sense for the terrain in my ride reports from Tour de los Padres, Pinyons and Pines, and Bones to Blue. This bike is my first with a 1x drivetrain, and in this post I’ll share my impressions and learnings from making the transition.
Quick primer: Bike drivetrains are described as AxB, where A is the number of chainrings up front and B is the number of cogs on the cassette in the back. So a bike with three chainrings in front and a 10 cog cassette in back is a 3×10. Thus “1x” is shorthand for any bike that has a single chainring in front and some number of cogs in back, most often 1×10, 1×11, or 1×12.
How easy or hard a gear feels when pedaling is a function of how many teeth are on the cassette cog (rear) and chainring (front). The easiest gear, also called the low gear, uses the biggest cog (most teeth) in back and the smallest chainring (fewest teeth) up front. The hardest / highest gear is the opposite: smallest cog and largest chainring. Of course, in a 1x setup there is only one chainring, and its number of teeth influences how easy or hard all the cassette cogs will feel.
Super-Brief History of 1x Drivetrains
To make a long story short, increases in cassette range are what allowed 1x drivetrains to flourish. With the mainstreamification (yes that’s a word) of 11 speed cassettes, it became possible for mountain bikers, and to some extent gravel riders, to get acceptable range with just a single chainring.
The technical and compatibility challenges are many and nuanced, but to sum up a few obvious ones: component manufacturers had to fit more cogs into the same amount of space, make chains narrower without sacrificing strength, and ensure that shifters and derailleurs can reliably make precise movements within this lower-tolerance system. Improvements in these areas and others led to the 11 and 12 speed cassettes increasingly common today.
Numbers We Care About
As cyclists, we care about all of this because it influences these important parts of our riding experience:
Low gear: This is the easiest gear, also called the climbing gear or granny gear (but let’s not make assumptions about Granny – maybe she can kick our butt on that hill climb). The lower it is, the easier to pedal a heavy load up a steep hill. If it’s not low enough, you’ll tire yourself out on climbs or have to get off and walk.
High gear: This is the hardest gear to pedal in, the one that helps you go fast on a gradual downhill or flat. If it’s not high enough, you’ll be “spun out” — moving your legs at an inefficiently high cadence — and won’t be able to go as fast on easy terrain.
Range: This is the difference between your low gear and high gear. A wide range allows you to have both a low enough low gear and a high enough high gear. If your range is too narrow, you’ll have to sacrifice at one end or the other.
Step: This is the spacing between each of your gears. If steps are too wide, shifting will feel awkward and jerky. If steps are too small, you’ll have to shift several times to feel a meaningful difference. You want the step spacing to feel natural across the whole range.
1x Gearing Tradeoffs
As you might expect, there are tradeoffs between those attributes. If you want a large range (so you can have a high high gear and low low gear) you either need more gears or larger steps between them. On a 1x the entire range must come from the cassette, but cassettes (and chains) have physical limitations. At the moment, most drivetrain manufacturers have only figured out how to cram 12 speeds into standard cassettes (a few have managed 13).
Thus a good 1x setup is all about balancing the need for a wide range with the need for reasonable step spacing, and then positioning that range in the right place relative to the high and low gears ideal for the terrain you’ll be riding.
If you need to be efficient on both steep climbs and extended gradual descents, a 1x might not offer enough range. This is why road bikes still use 2x or 3x drivetrains. But for mountain bikers, bikepackers, and other folks less focused on speed and pedaling efficiency and more focused on finessing rugged terrain (which tends to limit speed anyway), the current range of a 1×12 or 1×11 can be plenty.
Explaining 1x versus 2x With Pictures
“But will a 1x have all the gears I need??”
I hear your concern! The easiest way to answer this is to go through an example. Keep in mind that this is just one particular example; in fact it’s my 2×10 Fargo versus my 1×12 Stella. Not every 1x or 2x system will compare similarly.
First, what’s a gear ratio?
The term “gear ratio” comes up a lot when discussing drivetrains. A gear ratio is the number of teeth on the front chainring divided by the number of teeth on the rear cog. A higher number is a higher / harder gear, and a lower number is a lower / easier gear. So you can think of gear ratio as a way of quantifying the highness or lowness of any gear.
2×10 Drivetrain Example
My 2019 Fargo, named Shadowfax, has a 2×10 drivetrain with 38/24 tooth chainrings and a 10 speed cassette ranging from 10-36 teeth. If I calculate the gear ratios for each of those 20 possible combinations and plot them, I get the chart on the right here:
The most important thing to notice here: all that overlap! The red lines are gears that use the small chainring and the blue lines are gears that use the big chainring. In the middle you can see that they overlap and some of the steps are very small, making them nearly redundant.
So while technically we have 20 gears to choose from on a 2×10, in practice we don’t actually need all of them.
1×12 Drivetrain Example
Now let’s do the same plot for my new Stella with her 1×12 drivetrain. She has a 32 tooth chainring in front, and a wide-range 12 speed cassette with cogs ranging from 10 – 51 teeth in back.
You might be surprised to see that with only 12 gears, we’ve spanned almost the same range as the 2×10. That plot actually looks pretty good! Since there’s only one chainring, we don’t have any overlap. We also have reasonable steps throughout, making each gear uniquely useful. The step distance at the high and low ends is similar to the 2×10 above, but through the middle the steps are wider because we dropped the redundant overlapping gears.
2×10 vs. 1×12 Compared
To make this extra clear, let’s plot both on the same axis. This gets a little hard to see, but here they are with the same colors as above:
As you can see, these are the main differences between the two systems:
- 2×10 has a higher high gear
- 1×12 has a slightly lower low gear
- 2×10 has a wider range (but both ranges are pretty good)
What does this mean for bikepacking? Personally I find the gearing on the 1×12 meets my needs similarly to the 2×10. The lower high gear doesn’t bother me because I’m usually riding rougher surfaces and don’t need to be going screamin’ fast. The slightly lower low gear helps a bit with climbing. The steps, while slightly larger on the 1×12, still feel natural enough. Especially on undulating terrain, I actually appreciate the larger steps because I can get to the right gear with fewer shifts.
Don’t Forget the Cassette
We often talk about 1x versus 2x as if the number of chainrings is the only factor, but the cassette is equally important. Those graphs above compare a new 1×12 drivetrain with an older 2×10, but those aren’t the only options.
When we talk about a 1x drivetrain, we usually mean a modern setup with an 11 or 12 (or occasionally 10) speed cassette. The range of that cassette allows us to enjoy the benefits of 1x drivetrains while minimizing drawbacks. There’s a reason we don’t often see 1×8 drivetrains, for example — the range would be too small or the steps too large for most riders to tolerate.
When we talk about 2x or even 3x drivetrains, on the other hand, the cassette choice is more ambiguous. A standard 2×10 drivetrain from five years ago, for example, might have a similar range to a modern 1×12. But a modern 2×12 drivetrain that includes a wide-range cassette can have an ultra-wide range, larger than both a new 1×12 and that old 2×10.
Thus it’s hard to make definitive statements about 1x versus 2x without knowing more. 1x what? Most, but not all, of the 1x benefits and concerns I’ll explain below apply to setups with newer wide-range cassettes.
Benefits of 1x Drivetrains
The bike industry has been moving full-speed toward 1x drivetrains for mountain and many gravel bikes, and most people see them as an improvement over 2x and 3x. Here are the most substantial benefits of a single chainring.
Simpler mechanically: No front derailleur or shifter to maintain, adjust, or replace. No more annoying front derailleur chain rub! 🙂
Simpler mentally: No need to think about what gear you’re in up front, and fewer shifts needed (in some cases) to reach your desired gear.
Left hand is free to operate a dropper post lever, if you use one. This is another reason, in addition to terrain, why 1x drivetrains are especially nice for mountain biking.
Lighter: Depending on component choices, you can save a half to full pound by cutting out the front derailleur, shifter, chainring, cable, and housing.
More modern and technologically advanced: You may or may not appreciate the engineering that goes into modern drivetrains, but even if you don’t, it’s nice to know the bike industry is invested in developing and improving the parts you need.
Better chain retention: Without the need to accommodate shifts between chainrings, a single ring can use a narrow-wide tooth profile that holds the chain more securely. Along with the lack of shifting in the front, this reduces the risk of a dropped or jammed chain.
Wider steps (benefit on certain types of terrain): This one is either a benefit or drawback depending on the terrain. On undulating trails where the slope is always changing, wider steps help you reach your desired gear in fewer shifts. Mountain bikers tend to like this. On long sections of consistent grade, especially gravel or road, wider steps can force you to choose a slightly less efficient gear; you may feel that your cadence is slightly too fast or the resistance is a bit too stiff.
Frame geometry improvements: Without the need for multiple chainrings and a front derailleur, frame designers can create bikes with shorter chainstays, wider tire clearance, and other nuances of bike geometry that improve handling, especially in the gravel and MTB categories. The downside is that you can’t convert these bikes to 2x if you decide you’d prefer it.
Each of those items will matter more to some riders than others, depending on your goals and riding style. The question then becomes: how much will you enjoy these benefits, and are they worth the tradeoffs?
To answer this, let’s look at the most common concerns and misconceptions people tend to have about 1x drivetrains, particularly as they relate to bikepacking and touring.
Concerns About 1x Drivetrains
It’s one thing to consider the tradeoffs between 1x and 2x drivetrains for general cycling, but bikepacking and touring are a special case. We do strange things — like pedal heavy loaded bikes through all corners of the world — that can have a big impact on the suitability of certain bike components that “regular” cyclists wouldn’t think twice about.
Here are the typical concerns that many bikepackers and cycle tourers have about 1x drivetrains. I shared many of these when I began my research, but eventually I learned that some are well-founded and some aren’t.
Will my climbing gear be low enough for my loaded bike? Yes, it can be. With a suitably small chainring and modern wide-range cassette, most bikepackers can have a respectable climbing gear even when riding loaded. Those who ride with extra-heavy loads, like extended round-the-world tourers or folks pulling kid trailers, may be the exception.
Will my high gear be high enough, or will I be spun out on flats and gradual descents? This is a fair question, and the answer depends to some extent on your riding style. Among current wide-range cassettes it’s hard to do better than the 510% range of the popular Shimano 10-51t 12 speed. If you choose a chainring small enough to make climbing easy, you’ll limit the high end of your gearing and may not be able to power through flats and gradual downs as quickly. Most casual tourers and bikepackers aren’t bothered by this — we’ll just relax and coast or eat a snack on the go — but speed-hungry folks will miss their stiffer gears.
Will the wider spaces between gears make it hard to find the right gear? Technically yes, with fewer gears you can’t fine-tune your choice as carefully. 1x drivetrains can have wider spacing between gears and sometimes that spacing is less consistent. You might have to choose a gear that’s a tad too easy or too hard, or adjust quickly as you jump between gears.
In practice, mountain bikers and others who ride undulating terrain aren’t likely to be bothered by 1x step spacing, since the terrain is always changing underneath us anyway. Many leisurely loaded tourers won’t care either. The folks who do care are speed-focused racers who need to keep a highly efficient cadence while riding at a specific speed within a pack. If you come from a racing background and care about things like power and cadence, this might be a factor for you.
Will the parts be more expensive? Price depends on many factors, but all other things being equal, yes, newer 11 and 12 speed cassettes and chains are more expensive. Thanks to trickle-down technology, however, they are no longer restricted to the top-of-the-line group sets. Even 12 speed components are now available at standard levels and they can last a long time before needing to be replaced. It’s hard to quantify the expected difference in cost, but I think that compared to the overall cost of cycling and bikepacking this difference is unlikely to be a big factor for most people.
Will the parts be harder to find overseas? Yes, in many parts of the world 11 and 12 speed parts are not yet readily available. If you do a lot of riding in “developing” countries, your odds of finding replacement parts are better with an 8, 9, or even 10 speed cassette. Since this would be a pretty limited range with a 1x, you’ll probably want a 2x drivetrain. That said, replacing a cassette or derailleur in rural West Africa (or lots of other places) is a gamble no matter what.
Will I miss being able to make large shifts in front? With a 2x setup you can use the front derailleur to make large shifts quickly; with a 1x you must pass through each gear one at a time. Will this change bother you? It’s an individual preference, but many people adjust quickly. Some rear shifters have the ability to shift multiple gears at once. Combine this with larger steps between gears and you may not notice much difference.
Will an 11 or 12 speed derailleur be harder to keep aligned? Since 11 and 12 speed cogs have narrower spacing, it might seem intuitive that it’s harder to keep the gears indexed for smooth shifting. This might be true, all other things being equal, but it’s also true that derailleurs and shifters continue improving in terms of design and materials, which could cancel out that effect. My 1×12 is actually much better behaved than my 2×10, for whatever that’s worth.
Are 1x drivetrains less efficient? There is some research showing that 1x drivetrains suffer from slightly more friction due to differences in chain angles, tension, and speed. The measured difference is very small, and I challenge any bikepacker to notice it in a blind test.
Is this just a fad that’s going to go away? After doing my research and talking to the folks at Chumba who built my bike, I believe 1x drivetrains are here to stay. I think we’ll see continued innovation in cassettes as manufacturers figure out how to extend the range even more and bring down the prices of current 12 speed components. I don’t have a crystal ball, but I don’t expect any issues with parts availability or compatibility for quite awhile.
About 1300 miles ago I switched my primary bikepacking bike from a 2×10 Salsa Fargo to my new 1×12 Chumba Stella. For the style of riding I do on Stella — sometimes a hardtail with suspension fork installed, and sometimes a rigid mountain bike — I’m perfectly happy with the 1×12 drivetrain. Here’s what I noticed while getting used to it.
On singletrack, I strongly prefer the 1×12 to my old 2×10. The simplicity is a big benefit on terrain that requires frequent gear changes. I spend less time shifting and can get to my desired gear faster, with less mental effort. My low gear is even lower than before, so climbing is even easier. There are fewer components to worry about keeping aligned and safe from damage. I don’t notice any meaningful drawbacks.
On gravel and dirt roads, I slightly prefer my 1×12 to my old 2×10. The simplicity and durability are still benefits, but there are times when I wish I could cruise a little faster to take advantage of a smooth descent. Still, it’s not a big deal given that I’m riding loaded and usually not in a hurry.
On pavement with long stretches of flat and gradual downhill, I miss the higher high gear of my old 2×10. I can still make good progress but I don’t feel like I’m getting full efficiency out of my pedaling. If I were to focus on this style of riding I would go with a 2x, ideally a modern 2×11 or 2×12 for plenty of range (but even my older 2×10 would be better than my 1×12).
It’s hard to fully understand this benefit until you experience it. I didn’t expect to notice much difference, but now I’m a big fan of simpler 1x shifting. During the adjustment period I noticed that my brain and left hand kept trying to shift and then remembered, with a touch of relief, that there was nothing to do.
It’s a small amount of mental energy, but it can add up during hundreds or thousands of shifts, especially when there’s a lot going on with rugged terrain and rough surfaces.
After so many years of riding with a 2x (and even a triple on my road touring bike) I worried that a 1x drivetrain would take a lot of getting used to. By the end of my first local ride, about two hours, I felt I had pretty much adjusted. Out bodies and brains adapt surprisingly fast!
Everyone has their own preferences, but if you’re still on the fence here are some general guidelines based on what you’ll be using your bike for.
Mountain biking and singletrack, loaded or unloaded: 1x
Rough gravel and dirt roads, loaded or unloaded: 1x
Gravel and dirt road touring: 1x if you’re leisurely about it, 2x if you enjoy sometimes pushing for speed and/or want to sometimes race your bike unloaded
Pavement, loaded or unloaded: 2x
Long-haul international touring: 2×10 or 2×9 to maximize parts availability
Touring with extra-heavy load: 2x for the ability to have a lower low gear and still get a reasonable range
I haven’t talked much about 3x drivetrains in this post. That’s because the differences between 2x and 3x are smaller than the leap from 1x to 2x. I also think a modern 2×11 or 2×12 drivetrain offers a range that’s plenty wide for almost every bikepacker or tourer, without the additional overlap and mental load of managing three chainrings.
If you’re lucky enough to be choosing a new drivetrain or new bike, I hope this post has helped clarify your preference. But in the end, remember that both systems work well and have been used successfully by many a cyclist!
As someone with a 1x, 2x, and a 3x in my garage, I think our bodies and brains are remarkably good at adapting to whatever system we’re working with at the moment. They’ll all get us down the road and around the next corner, which is what exploring by bike is all about.
More Bikepacking Resources
If you’re into bikepacking, you might also like these:
- Bikepacking With A Backpack: When is it a good idea?
- The Great Divide Mountain Bike Route: Essential Q&A
- Preventing Bike Theft While Bikepacking or Touring
Or, visit the bikepacking and cycling category page for lots more!
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