I’m going to call myself out: Sometimes I can be a luddite. I might dig my heels in from time to time. I like things the way I like them, because clearly that’s the best way, right? However, I’m also prone to jumping ship rather quickly once I find a better way.
Today’s discussion will center around 1x drivetrain systems (also known as single chainring or “one-by” drivetrains), and how my attitude towards them has changed over time.
If you’re a complete beginner to this concept, the short of it is that there are some relatively new bicycle drivetrain systems out there that use one front chainring instead of two or three. You might wonder, “Doesn’t that mean that I can’t climb hills any more – don’t I need that small front ring?”, or perhaps, “Doesn’t that mean I have a lot less gears to choose from?”
The answers to these questions range from ‘yes’ to ‘kinda-sorta-maybe’. There are two key things that have helped to minimize these downsides: 1) adding more gears to the rear cassette, or gear cluster, and 2) increasing the difference in size between the smallest and largest cassette cogs.
In the past, my arguments against 1x revolved around these issues. Compared to a two or three-ring system, you simply cannot retain the same overall gear range (highest gear ratio and lowest gear ratio) AND have the same size “jumps” in ratio with each shift of the rear derailleur. It’s an either-or. A single chainring system with a wide-range rear cassette retains the overall gear range, but when you shift gears out back, the change in pedaling effort will be greater than on a double chainring system with a smaller range cassette. For some, this is a deal-breaker. For me, I’ve changed my views and see some situations where this trade-off becomes worthwhile and preferable.
Below, I’ll detail what I think are the best situations and arguments in favor of 1x.
Above image © SRAM
1x for Beginners and Non-Tech-Geeks
Some argue that having fewer gears to choose from is actually a benefit, and I’ve come around to this idea – especially for beginners, or people who simply are not technical in a nature. You’re cutting the decision-making requirement in half. Rather than having two shifters to deal with, there’s one. All you have to decide is “easier” or “harder”. With a two-chainring system, you might shift to the large chainring in front to make your effort harder (or go faster), but often times the change is too much. So – then you have to shift in the rear a few times (easy-easy-easy) to compensate. Instead of shifting once, you shift three or four times total. While this eventually becomes second nature to most cyclists, it remains a challenge or distraction for some. If we want to get more people in to cycling and triathlon – people who don’t necessarily center their identity around it – the benefit of simplicity cannot be overstated.
If you think this argument is stupid and that it’s not hard to manage two shifters, there are plenty of great 2x or 3x drivetrain options out there for you – hooray! I have personally set people up on 1x specifically for the purpose of simplifying their relationship with their bike, to great success. It’s not for everyone in every place. So far, I’ve seen it work well for people that live in flat-ish areas (i.e. without extreme mountain ranges in their normal riding repertoire). I’ve seen it work well for beginners, and specifically women. I don’t intend to sound sexist, but I think it’s safe to argue that – on average – women aren’t as interested in technical or mechanical pursuits as men. I find that some people actually shift gears more often with 1x, because they feel less overwhelmed by decision-making. They actually start to use what they have.
Thankfully, 1x systems are starting to hit lower price points, because I think this is where we need them most. I don’t yet see many entry-level road bikes with 1x drivetrains, but I hope this happens sooner rather than later. This is the greatest opportunity for growth in 1x. The first-timer buying a road bike for $750 is more likely to benefit from 1x than a lifelong cyclist who owns 5 bikes.
Above image © Wolf Tooth Components
1x – the Savior of Mechanical
Over time, electronic shifting has grown in popularity, and I expect that trend to continue. It has hit lower price points, but remains a premium product in 2018. It works best when your frame is tailor-made for electronic shifting, however, and doesn’t always play nice with older bikes. In a way, electronic shifting accomplishes a lot of what 1x drivetrains do, by making it easier to manage the drivetrain while riding (however, it also has a much more complicated installation process, requires battery charging, and requires decision making about two shifters – short of the growing option for synchro shifting, which can auto-select both front and rear gears).
Given the above, my prediction is that 1x drivetrains are be the place that cable-driven mechanical drivetrains will survive and thrive long-term.
Doesn’t it make sense? The maintenance is easy for 1x. It can be billed as the super light weight option – no batteries, no front derailleur, only one chainring. It’s most certainly going to be cheaper than a full-tilt 2x electronic system. If you’re on a budget, want a light-and-simple setup, and don’t mind the larger gear jumps out back, here’s your solution.
Don’t get me wrong – I think double chainring mechanical systems will stick around. However, much in the way that triple chainring systems have slowly been reduced over time, I think we’ll see fewer double chainring systems – at least those that are mechanically actuated.
Speaking of triple chainring systems (which were very common only 20 years ago), I actually see 1x as being quite similar. Think of it – with a triple chainring, the middle ring is your bread and butter. You might spend 70% of your riding time in that middle gear, because its size is perfect for your flat-to-rolling terrain. Then you spend 15% in the big ring, and 15% in the small ring for climbs and descents. Many of those “old” triple ring systems had 9 gears in the cassette. Today’s most common cassettes have 11 gears – adding one to each end of the old 9-speed. In a way, those two extra gears are trying to replace the big and small chainrings of the triple system. Adding or subtracting a couple teeth to the rear cassette sizes makes a bigger impact on your overall gearing than the same change to a front chainring, so this actually works out fairly well.
Using Sheldon Brown’s fantastic gear calculator, I ran some quick numbers. Let’s look at three potential front chainring sizes – 48, 50, and 52 teeth. Let’s also look at three rear cassette cog sizes, which are commonly used for the smallest gear position (i.e. your highest or hardest gear out back) – 10, 11, and 12 teeth.
Many older triple systems would use a 52 tooth big ring and 12-tooth small cog, netting a speed of 30.6mph at a pedaling cadence of 90rpm. Modern 1x systems now use an 11 or even 10-tooth small cog, and as you can see they give a sizable boost in speed, even with smaller size chainrings. With 1x, you can choose a chainring size that’s about the same as the middle ring of a triple, and voila!
Oval or Otherwise Non-Round Rings
This one doesn’t require a long explanation. Without getting in to the technical details, some people prefer to use front chainrings that are NOT round. Manufacturers of these chainrings typically claim that they offer some combination of more power, less rider fatigue, or a more efficient pedal stroke. You can find them from companies such as Rotor, Wolf Tooth Components, Osymetric, SRAM, and others.
The downside of these rings is that front shifting is almost always compromised to some degree. Using the right mix of derailleur, adapter, chain, and fine tuning, you can often get the shift quality to be good – but it’s almost never as good as a “pure” drivetrain system using round rings, such as a Shimano Dura Ace crankset, chain, and front derailleur.
For this reason, I also predict that 1x systems will be the place that oval chainrings will survive and thrive long-term. No front shifting – no problem.
Above image © Competitive Cyclist
Again, this one doesn’t require a huge discussion, but so far it seems that the jury has decided: Removing the front derailleur (and the front derailleur mount, when possible) provides an aerodynamic advantage. How much? Is it enough to matter? I’m not sure. It’s not nothing. It’s also not enough that I’d push someone to 1x specifically because of the aerodynamic advantage, if they had other factors that said they’d be better overall with two chainrings.
For now, I’ll link to Jordan Rapp’s 1x article written for Diamondback, which centers around chain friction, but also touches on aerodynamics – Check it out.
Certainly we’ll learn more about this as time goes on.
The Biggest Downsides?
What, if any are the biggest downsides to 1x? Who is it NOT for?
While I’ve come around – a lot – to the idea of 1x, I still don’t think it’s for every person in every situation. If you’re doing the Leadville 100 mountain bike race, it’s probably not for you (in my opinion – there is just too much altitude gain and loss). If you’re highly sensitive to cadence changes, it’s not for you.
The biggest problem I see is with indoor riding. This is where a narrow range cassette seems indispensable. With most indoor trainers that I’ve ridden, you feel the gear changes more than out on the road. This seems especially true for fluid-based trainers, or those that otherwise have enough resistance to do a “real” workout. Also, many people ride indoors when they’re crunched for time or want to hit very specific intervals – at a specific cadence or heart rate – because that’s not always possible out on the road.
Above image © CycleOps
Yes, you can change your cassette on a 1x bike to accommodate this – if you have time in your busy work week to do so. Yes, you can use a dedicated bike that you only use for the indoor trainer – if you have the budget and storage space. If, however, you’re using ONE bike for both indoor and outdoor riding, and don’t have the time to change cassettes frequently, a 1x system is probably not for you – especially if you live in a hilly area that would require a very wide-range cassette. I do think that there is an open opportunity for more cassette sizes to be made. If you want the super-duper 10-tooth cog from a SRAM cassette, the smallest size you can get for the large cog is 42 teeth. That’s giant. For 1x to really catch on for road cycling, I think they need to bring out a 10-32 and 10-36 sooner rather than later. Note that the cassettes with a 10-tooth cog do require a special “XD” freehub for your wheel. Or, they need to offer larger sizes for their cassettes starting with an 11-tooth cog, such as 11-40 or 11-42.
I have one last point, which is related to the above problem, and might also help to convince some anti 1x-ers to consider its merits. I think that 1x might be good for you specifically because it isn’t perfect. You might not have the perfect cadence at the perfect time for your perfect workout. Some triathletes might – just might – have a reputation for being a little uptight. I may or may not have been guilty of this in the past. Just a little. I swear... the glove didn’t fit! You must acquit!
In the same way that people have used single speed bikes to help train their legs and mind, I think that a 1x system can increase your cycling cojones. You might consider doing what I’m planning to do, which is have 1x on my “road” bike (which is actually more of a cyclocross-fat-tire-drop-bar-bike – which I effectively use as a road bike), and then a traditional two-chainring system for my triathlon bike. If I’m doing an indoor trainer ride, I’ll pick the tri bike 100% of the time. If I’m out for a fun road ride with friends, or an otherwise non-serious ride, I’ll pick the road bike. In fact, the bike I’m building will be my first long-term relationship with a modern 1x system, and I’m quite intrigued to see how well it sits with me at this stage in my cycling and triathlon life. Expect much more on that bike and my drivetrain ramblings coming soon.