You can fly an Eagle 1×12. Yet some remain committed to 2×11. Why?
When you look at kids riding their first proper bike, you probably remember your own. And the one distinguishing feature is that we all start with a single blade mounted to that drive side crankarm.
The desire for gears are real and eventually you get a cassette at the back, then an additional blade up front. When drivetrains evolved to a configuration with gears in the double-figures, very fit people started wondering if they really needed two blades up front, if they already had ten gears at the rear. Logically, if you dropped one blade and a front-mech, that saved weight, and you had some real-estate available on the handlebar to fit all manner of other functional things, such as lock-out controls, a dropper post remote – or perhaps that most underrated South African rider etiquette feature: a bell.
In 2010, if you walked into a bike shop, nearly all the demo bikes were running 2x drivetrains. Today, it’s a world 1×11 and if you wish for the calming spread of ratios of your fondly remembered 2×10, a new 1×12 drivetrain can do that. Those who have ridden both will confirm that 1x systems are superior. Less complexity, cleaner handlebar, better side-profile bike aesthetics (yes, that is a thing for many people) and perhaps most importantly: silence and an absence of chain suck risk.
It’s possible to descend technical trails at speed on a 1x system with rim strain and damper action being your only accompanying acoustics. Ride a 2x system down the same trail and you keep glancing down to confirm that the drivetrain is still all of one piece, considering all the noise it generates. It’s a simple ‘1x for-the-win’, right?
Well, that’s the contentious issue. If you are a descending biased rider, undoubtedly, but could there remain specific benefits to the 2x system for stage racers? I’d observed that riders from European Alpine countries have no contrition about running 2-by and after requesting somebody much cleverer than I to test the theory in some engineering software, the results have been interesting.
Although a current 1×12 drivetrain has the potential to equal a 2×11 system’s spread of ratios, the inevitability is that in a climbing scenario, you’ll still be using a much larger front chainring. On a dual-suspension bike, the influence of that larger chainring induces a potentially greater energy loss by not optimising the anti-squat characteristics engineered into dual-suspension bikes. The difference is small, but on a few long, gradual climbs, it is sure to compound.
True, the 2x system is slightly heavier overall but on a long climb, the compound effect of its slightly greater rotational mass could be argued as less of a fatigue inducement than having a 34- or 36-tooth chainring. How? Much like an economist, I’d advise you to look at the graphs.
You’ll notice that similar climbing gear ratios deliver vastly different anti-squat percentages. Neutral anti-squat registers as 100%. The 2x system has a number greater than 100%, meaning that the influence of a rider pedalling, has a notably reduced effect on suspension movement. With the 1×12 your anti-squat number is below 100% (worse), which means you’ll suffer incremental effort losses through factional suspension movement over the duration of a long climb. The reason is that a smaller ring front ring is superior during climbing, is that it operates the chainline on rotation below the chainstay pivot point, which you can see in the accompanying drawing.
“But wait, I have a remote lock-out switch.” Indeed, remote lockouts are the Blackmagic which theoretically convert dual-suspension bikes to default hardtails when required, but a meticulously designed and executed suspension system should operate without much bother in the open setting.
The advent of 1x drivetrains have been a blessing for most. Quieter bikes, with less handlebar clutter, and incredible chain-on-ring security when descending technical terrain at speed. They don’t suck chains in muddy conditions either. For most applications, the 1x drivetrain deserves all the acolytes we bestow upon it.
Yet the continued presence of 2x systems shouldn’t be that surprising in a country where paradoxically, we have very large riders, who love competing in long-distance stage races. That 1×12 system might have a theoretically amazing spread of ratios, but for some, having a smaller secondary ring up front, to boost anti-squat way beyond that neutral 100% value during an ascent, will be of greater value than the weight penalty it implies, when the long climb start escalating in gradient percentages.
And when the bunch starts edging up in speed, it’s a lot less fatiguing to keep up the cadence, when you have smaller incremental steps between the gears. It’s why the 2x simply refuses to die.
