Heading out the door? Read this article on the new Outside+ app available now on iOS devices for members! Download the app.
While more may be better in many aspects of life, SRAM’s latest 1×11 Force 1 and Rival 1 components aim to simplify and minimize your bike with the elimination of a front derailleur and a single front chainring. While the 1x setup has been accepted for mountain bikes, finding a gear combination that accommodates the variety of speeds of road riding seems to be much harder, but the team at SRAM say they have done it with the introduction of Force 1 and Rival 1.
A Bit of History
Before diving into the nitty gritty of the two new groups, here’s a little background on the 1x idea, starting with mountain bikes. From cross country pros to weekend warrior trail riders, 1x mountain bike drivetrains have exploded in popularity over the last few years. Noticing a perfect niche in the mountain market, SRAM expanded their line into the cyclocross world when they launched their CX1 group in March of 2014. CX1 received great reviews thanks to its ease of use and the impossibility of dropping a chain. Force CX1 is nearly identical to Force 1, the only difference is the chainring doesn’t have mud shedding grooves. Functionally and mechanically, everything is the same, which is a good thing. SRAM took a “if it’s not broken, don’t fix it” approach to the new 1x road drivetrains.
How Does it Work?
At first glance, one might ask why a 1x group is necessary because removing the front derailleur and small chainring are the same thing, right? Not hardly, these groups are much more than a couple of removed parts. There are two main aspects of SRAM’s Force 1 and Rival 1: the chainring and rear derailleur. The front chainring has teeth that are manufactured in a narrow-wide fashion known as X-Sync. X-Sync is a German engineered technology that features both tall square teeth that engage the chain earlier than traditional teeth, as well as sharp and narrow teeth that manage cross-chain situations. In short, the chainring is developed to mate perfectly with the chain providing a simple, quiet drivetrain. While the chainring does a lot for keeping the chain from derailing and the drivetrain running smoothly, the other piece of the puzzle is the rear derailleur. The rear derailleurs on all of SRAM’s 1x systems (and 2x mountain applications) include SRAM’s Roller Bearing Clutch Technology. The clutch (the part of the derailleur located by the cage that looks like a knuckle) keeps the chain taught during rough roads or changing gears. This drastically helps prevent derailment and chain slap, while providing a crisp, accurate shift.
It’s important to acknowledge that 1x drivetrains are not a cure-all for every rider in every application and 2x systems will still be the best option for many cyclists. However, one chainring up front has some serious advantages, including an aerodynamic improvement.
If you’re hoping to lighten your load of our TT bike, switching to a 1x drivetrain won’t help. With identical cassettes, a 1x system on a road bike saves approximately 170 grams, which comes from the removal of the internals of the left shifter. On a TT bike, most triathletes will likely use a larger cassette than if using a 2x system and will run a dummy front shifter. For the same reason TT bikes sacrifice weight for aerodynamic benefits, adopters of 1x will not be shedding any weight but getting an aero advantage.
While SRAM hasn’t released any extensive wind tunnel tests, preliminary results show some very promising numbers for 1x drivetrains when it comes to drag. With 1x, you lose some bits that sit in the wind: front derailleur, front derailleur cable, inner chainring, and most importantly the front derailleur mount. From the time that was spent in the tunnel, the biggest gains seemed to come from the removal of the front derailleur mount. With 1x becoming a mainstream group option, this opens up a whole new area for the development of super bikes.
Almost everyone has experienced the frustration of dropping a chain. Getting a chain sucked in between the chainring and bottom bracket can be one of the most annoying things about riding a bike. With 1x, you’ll never have to worry about dropping a chain again. It has been tested to hold up against even the roughest dirt roads. Throw whatever you want at it and the narrow wide tooth profile keeps the chain locked on. The other great aspect of this drivetrain is how quiet the drivetrain becomes with a 1x setup. For years, bike chainrings have been made to properly get the chain off of the chainring, not keep it on, and this in turn brings drivetrain noise. With SRAM’s 1x system, the chainring was manufactured to mate perfectly with the chain, thus allowing for a quiet and efficient relationship.
One of the most difficult aspects of running a 1x system is figuring out what gearing to run. SRAM has done their best to provide a variety of chainrings and cassettes in order to help fill the gear ratio gap between 1x and 2x systems.
46t, 48t, 50t, 52t, 54t
With all these options, the question becomes what combination is best? The problem is that there’s no real answer to this question because it is highly dependent upon terrain, power output and cadence. The best advice for what combination to pick comes from pro triathlete Ben Collins who has been running Force 1 for several months. Collins says to choose a chainring that allows you to spend the majority of your time in the one tooth jumps, and then use the lower cassette gears for bailouts. This allows for a more even cadence curve when you stay away from the two and three tooth jumps. With its proven success in mountain and cyclocross applications, 1x for the road will be a great option for many riders.