Is 1×12 the future of drivetrains?


When the Sram Eagle 1×12 was launched, we were there to test it, and we had a good impression. Much to our surprise, it worked better than the 1×10 drivetrain we were using at that point, and even bested the 1×11 system present on enduro bikes. On the 1×10 drivetrain, we used an 11-36 cassette and 30-tooth chainring, while the 1×11 had an extra 40-teeth cog added to the cassette. The interval between the lowest and highest sprocket matters, but so do the ratios provided by each of the cogs.

Big, bigger, the biggest! 2017 brought mere mortals the 50-tooth cog. Good news?

Shifting to a 2×11 transmission system made it clear that this one covered any thing you could possibly need, but we know very well that single-chainring systems won a lot of fans, which are unwilling to fall for the double-chainring, 11-tooth system. A big plus of the 1×12 system is weight, while straight-forward usage, that needs no kind of explanations regarding how it works, gains more ground for it.

Chainring with 30 teeth. My favourite sight!

Looking back, Sram rocked biking world back in 2012, when it launched the first single chainring drivetrain. Some were skeptical, some were excited, still numbers brought enough light over the matter of success – they were a sales hit that provided the manufacturer with enough boost to reasearch and develop over-10-cog cassettes, which stopped at the 12-tooth one. The impact was so big, it is unclear whether the 12 sprockets or the 50-tooth, big-as-a-mini-pizza cog caused it. Maybe not enough noticed, but it took engineers only a few years to grow the largest sprocket from 40 to 50 teeth. However, having a single chainring can cause disruption between ratios. In the case of the 1×12 system, ratios follow the 2-2-2-2-3-3-4-4-4-6-8 pattern, values that closely follow the number of teeth: 10-12-14-16-18-21-24-28-32-36-42-50. For 1×11 drivetrains, the gaps follow the 2-2-2-2-2-3-3-4-4-4-6 string, which means that put head-to-head, the 1×11 has a lighter leap in the middle (en extra 2), but it lacks a ratio that allows climbing steep hills. Simply put, the 1×12 system helps you climb hellish hills, but is less permissive in the mid-range.

Maybe mud is geeting in the way, but this derailleur looks high tech, because it really is high tech

Yet, if you are not racing, you won’t feel that extra ratio from the mid-range missing. You will, in exchange, feel it when hard climbing occurs, because if you will use a 30-tooth chainring with a 50-tooth sprockes, you will deal with a ratio similar to one between the small ring of a double chainring drive and its lowest sprocket.

1×12: 0.6 climbing ratio (30-tooth chainring and 50-tooth sprocket)

2×11: 0.61 climbing ratio (26-tooth chainring and 42-tooth sprocket)

1×11: 0.71 climbing ratio (30-tooth chainring and 42-tooth sprocket)

In regard of speedier ratios:

1×12: 3 speed ratio (30-tooth chainring and 10-tooth sprocket)

2×11: 3.2 speed ratio (36-tooth chainring and 11-tooth sprocket)

1×11: 3 speed ratio (30-tooth chainring and 42-tooth sprocket)

No doubt you’re better of with a Sram Eagle 30-tooth chainring and 50-tooth sprocket when climbing. For riding faster, 2×11 have a better solution, but not overwhelmingly superior. Using the 42-tooth sprocket with a Shimano double drivetrain fitted with 24-34 chainrings leads you to a 0.57 ratio, while the best it can do in terms of high gear is 3.09. Values do not differ too much, but weight drags Shimano down, since it has an extra chainring, derailleur, shifter and cable + hoods.

Shifting made simple using only one shifter.

Should I jump on the 1×12 bandwagon?

Yes, you should, only if:

  1. Budget allows it. A Sram X01 Eagle transmission, which includes the rear derailleur, shifter, cassette and chain sets you back 620 euros. A Shimano 2×11, packing extra the bottom bracket cartridge, chainset and brakes costs 559 euros. The 1×12 doesn’t include the chainset, so a single-chainring one adds cost to your bill. Ergo, huge price difference.
  2. You are ready to pay for low weight. The lack in grams is, all-in-all, impressive. The Shimano double chainring set adds up to somewhere around 1,5 kilograms (chainset, cartridge and brakes not included, while Sram barely manages to tip the scale over 1 kilo.
  3. Compatibility is no headache for you. If a 2×11 drivetrain isn’t rocket science in terms of fitting and mounting, the 1×12 set requires a XD cassette on the rear hub. This puts another 102 euros on the bill.

The last time we tested a 1×12 drivetrain, was riding an enduro mountain bike with 170/165mm suspensions. Climbing on it seems like a grueling task (and it actually is), but travelling time wasn’t at all bad compared to a 2×11 29er, also taking into account the wider tires, smaller 27.5 wheels and rear shock. Shifting is a simple operation, no need to ask yourself what chainring should you use, and it also is very precise and accurate, while the existing ratios where enough. It also comes to show that the 1×12 suits bikers that roam the mountains all the time, and it isn’t a system neccesarily made for professional sport. One thing you will have to see for yourself is the chain wear, since it’s stressed not only on by the pulling of the chainring, but also by lateral exertion. You can also block the pulley of the derailleur when removing the wheel, and you can change the chainring very easy in order to adjust the settings to the terrain profile. We ourselves are suckers for the 30-tooth chainring, but you can add the 32, 34, 36 or 38 option for 76 euros each.

The 1×12 drivetrain offers a lot of options and comes with a lot of pros. You can only be discouraged by the price, and not only how much the set itself costs, but the other parts that are not included. Stepping over the 1.000-euro threshold in this case is almost a certainty.

If this is how the future looks like or not, it’s up to us to wait and see. Experience has shown us that if a product is a hit from the start, then it’s set for super-stardom. So, for the moment, we can surely say that the future of the 1×12 system looks promising.