Several years ago, a Cervelo engineer made a quip that he never thought would become a major talking point in triathlete circles. In an email to TriRig, Damon Rinard wrote, “FYI: that FD mount alone has more drag than the whole down tube.” Damon was talking about the new P2 specifically, but the point is likely true for a great many bikes these days. Down tubes are nearly perfect airfoils, and produce very little drag, whereas the front derailleur, electronic ones especially, are fairly poorly optimized from an aerodynamics standpoint. In the triathlon world, aero is everything, so why not run a single chainring setup and be done with it? SRAM had the same thought, and with Force 1 they have promised a light, reliable, and aero setup for triathletes. Can simply removing the front derailleur and swapping a chainring really make that much difference?
The Force 1 groupset comes with a particularly tricky rear derailleur that forms the heart of the system. It uses a roller bearing clutch that keeps constant tension on the chain, eliminating the chain slackness that causes chain slap or worse, dropped chains. The derailleur cage also features a “straight parallelogram” design that SRAM is calling “X-Horizon,” which keeps the cage itself perfectly vertical, even at the top or bottom of the cassette, which ensures that the only time the system changes gears is when you pull the shifter.
Changing wheels is a breeze, too, thanks to the CageLock feature. Fully extend the derailleur cage forward and press the lock button and the entire cage swings freely and you can slide the rear wheel out of even horizontal dropouts without having to get chain grease all over your hands. Swapping between training and race wheels has literally never been easier.
Force 1’s crank is the standard carbon-armed Force crank from the base groupset, but the chainring possesses a very different tooth profile than the normal cranks do. Where standard Force chainrings are sharply raked and the teeth are pointed, the single chainring design of Force 1 has flat teeth that are more squared off, which means that the chain engages with the crank teeth sooner and with less slap. This sounds like a small change, and it is, but it changes how the entire groupset feels through the pedals. You feel far more connected to the drivetrain than normal, and the moment of transition between freewheeling and pedaling again has a very binary feel to it; the moment of take-up when you being pedaling on a normal drivetrain is gone. All of this adds up to better communication from the drivetrain to your legs, and a feeling of connectedness that doesn’t go away. With Force 1, you and the bike really are a single unit.
Of course, riding a single ring setup isn’t all sunshine and rainbows. Selection of gearing is vitally important, given how you have potentially half the options available to you than on a standard drivetrain. Take a look at this chart. On the left side is a 53/39 double ring setup with an 11-28 cassette, which is fairly common for triathletes. On the right is a single ring, in this case a 52, with the same cassette.
From this it is clear that there is little change from your big ring to the single crank. At best, you’re moving the effective gear ratio by a single cog where the 52 chart and the 39 chart overlap, but otherwise not much is really happening. That’s okay if you, like us, live in Florida and have only shifted into the small ring on a causeway or similar. But what if you live somewhere with rolling hills, or worse, mountains? Well, the rear derailleur can accept a cassette range all the way up to 42t, which would be plenty for even the most novice climbers among us. Let’s take the middle road, then. 11-30 should do the trick.
Much better! Now, our top two gears in the 52×11-30 are only a little bit harder than 39×21 and 39×23. This should enable you to climb just about anything short of Alps D’Huez, and though there is a triathlon there, you could easily tackle it with an 11-32 cassette on the same 52t chainring. That’s the beauty, and the curse, of a x1 setup: it’s all about cassette selection.
With 11 cogs in modern cassettes, we only really use the last five, perhaps six, on the majority of our rides. We can afford to move to cassettes with larger cogs at the back and the same 11-17 that we know and love at the front, especially since we can make those two and three tooth jumps earlier with how good modern derailleur technology is. We don’t have to fear dropping our chain anymore to deal with the road acquiring a gradient. Click your bar-end up three and just keep right on going. There’s something to be said for that kind of simplicity, even if it requires a little more forethought in the selection of cassette for your ride.
Here’s the thing, though. Cassettes are cheap. With an MSRP of $100, you can have a spare and still be in for less than a double chainring setup (derailleur, shifter, cable, etc.), maybe even two spares, depending on how good a deal you can find. With Force 1, you get more mechanical simplicity, less weight, more features, and less cost than the standard setup. Yes, you lose a derailleur and a shifter. But in the world of triathlon, since when has less weight been a bad thing?
After riding Force 1 for a while, it was hard to transition back to a double chainring. More to tweak, more to check, more noise as the chainring runs through the derailleur and has to mate with the chainring, and more to think about when shifting. With Force 1, you get to think about less when you’re on the bike and instead focus on the task at hand, riding. Sounds good to us. SRAM has outdone themselves this time, and if you’re in the market for a new groupset, or even a new bike, take a serious look at the idea of a single ring setup. Force 1 has made converts of us here at AeroGeeks, and we think it just might make a convert out of you, too.