Now they've killed the front derailleur! Horrified comments haunted the online bike forums when component manufacturer SRAM presented its first 1x11 groupset in 2012: only a single, solitary chainring at the front, no front derailleur, no shift lever on the left! Up until then, more gears on a bike was still considered desirable. And now suddenly less should be more?
Competition between systems
The excitement at the time has now died down: Single derailleur gears are accepted as another standard in the maelstrom of technical evolution. Today, mountain bikes are almost exclusively equipped with 1x12 drivetrains. This is because competitor Shimano has also simplified its mountain bike groupsets in the meantime. However, the Japanese have not sacrificed the front derailleur: they give the buyer a choice. The latest version of the MTB-XT can be operated with one or two chainrings.
Single instead of double cranks are also increasingly being seen on gravel bikes and related adventure, off-road and commuter bikes. For mid-motor pedelecs for touring and everyday use, and even more so for e-mountainbikes, the single-blade crank is mandatory anyway: only a few motor systems leave room for a second chainring. So are touring bikes and all-rounders suitable for touring the last bastion of the venerable triple chainring, which once made the completely new, revolutionary mountain bike possible in the first place?
Continuous evolution
Firstly, it should be noted that all manufacturers are continuously developing their derailleur systems. The state of the art for 3x10 systems is Shimano's XT Trekking. This is followed, in descending order of quality, by the Deore, Alivio, Acera and Altus groupsets, the latter two of which can only be fitted to older bike models with nine-, eight- or seven-speed cassettes. All have triple chainrings.
Shimano has developed the mountain bike line separately: The XT, SLX and Deore groupsets carry twelve-speed cassettes and single or double cranks. Competitor SRAM, on the other hand, relies exclusively on single gears on mountain bikes with twelve sprockets at the rear. Their dimensions have also developed enormously: The smallest sprocket has ten teeth, the largest 52 teeth - on a cassette, mind you!
This required a few technical tricks. This is because the cassette must not become wider with an additional sprocket; the space on the rear wheel and its axle width dictate the dimensions. In addition, sprockets with only ten teeth no longer fit on the freehub body of the rear wheel hub due to their smaller inner diameter. Shimano and SRAM therefore had to develop new freewheels for their ten-tooth sprockets. The tooth profiles on the single chainring are moulded three-dimensionally so that the chain runs over them both quietly and safely. The rear derailleurs of both manufacturers work with reinforced tensioning mechanisms to prevent the chain from jumping off on bumpy roads. Enlarged guide rollers on the rear derailleurs keep the chain length in check without having to lengthen the rear derailleur cage. The narrow chains are made fit with reinforced material, specially moulded plates and pins and, in some cases, enlarged roller diameters and high-tech coatings so that they can circle around the chainring and sprocket with low friction and durability despite heavy skewing.
Compared to a triple gear system, the single gear system saves a few hundred grams of weight, depending on the version. The more important advantage is its simpler operation: one hand triggers all gears one after the other on a gear lever. However, despite further technical development, the shortcoming remains that even a high-end single gear system is nowhere near the gear range of well-tuned multi-gear systems. Where it comes close in comparison to some double systems, it still lacks either large gears for fast riding or smaller gears for the mountains for universal use. In addition, the speed jumps when pedalling from gear to gear are greater with the smallest gears than with multi-gear systems with less widely spaced cassettes.
Who needs what?
If you prefer to ride on roads and paths and don't want to get the most out of your bike, you can get by with a single gear. You just have to accept that the lack of gear ratios limits performance. Off-road and at relatively low but dynamically changing speeds and many changes of direction, the single can also score points. The intuitive shifting with a lever has a clearly positive effect here. On routes in hilly or even alpine terrain, the lack of a second chainring for a wide-ratio gearbox is associated with disadvantages; for tours with luggage in mountainous terrain, the triple crankset is indispensable.
Especially on long journeys, when your energy levels drop, you will be glad to have the smallest chainring as a "lifebuoy". Road bike drivetrains such as Shimano's Ultegra, 105 or SRAM's Force find their place on randonneur bikes for sporty travelling or commuting. Here too, two chainrings enable a variety and range of gear ratios that make challenging routes rideable in the first place. The same applies to Shimano's gravel components of the GRX groupset and the twelve-speed XT, SLX and Deore groupsets for mountain bikes. The fact that many trekking cyclists do not utilise the potential of their triple drivetrain and often only leave the chain on one of the three chainrings should not be an argument against 3x10. Many e-bike pedallers have never run their bike's ample batteries flat - but it simply gives a feeling of security and independence that you could. This also applies to the reserves of the triple chainring!
Conclusion:
The three shifting systems represent different areas of application. Technically, they are on a par with each other. The only difference is the variety and gradation of gears
You can download the detailed article on the derailleur system comparison as a PDF for a fee.
