The best smart bikes for Zwift — a head-to-head group test

Zwift did not create indoor training or the concept of training software, but it has fueled a rapid expansion of the interactive hardware available to riders to make indoor riding more fun. Smart bikes are the latest category of interactive training tools. They combine the measured and dynamic resistance of smart trainers with the convenience of a dedicated indoor bike.

Over the past three winters I’ve tested a couple dozen smart trainers, and this winter I tested four smart bikes: The WattBike Atom, the StagesBike, the Tacx Neo Bike, and the Wahoo Kickr Bike. 

It’s important to note that smart bikes are different than a normal indoor bike like you may have used in a gym or even the higher-end electronic home models like a Peloton. The primary difference is that smart bikes are cyclist-focused, wattage-based tools designed to integrate with third-party software like Zwift, TrainerRoad, and FulGaz. Peloton, NordicTrack, and others have their own closed ecosystem for workouts and classes. These can be great tools for the gym-class crowd, but if you’re looking for power-based training and virtual racing, they don’t work.

I tested each of the four smart bikes in Zwift group rides, workouts, and races. I’ve logged 5,300 miles in the game on a variety of smart trainers, so I have a decent feel for the options out there.

Each smart bike has its own quirky personality, and the differences between bikes are far greater than the differences between smart trainers of a similar price point. The stability, fit, adjustability, shifting, and accommodation for tablets and phones vary greatly. 

Conversely, I found all four bikes to deliver reliable measurement that I would happily use for training, with less variation from one to the other than with some smart trainers. For power reference, I used a set of Garmin Vector 3 pedals that I have in turn tested against meters from Shimano, Quarq and Stages. Also, in terms of noise, all four smart bikes are relatively quiet, in the 60dB range when doing 200 watts at 90rpm.

Wattbike Atom | $2,599

Pros: Excellent stability, good leg clearance, integrated tablet holder

Cons: One (170mm) crank length, no accessory tray or USB charger, Allen bolts required for many adjustments

The British WattBike has long found favor among national teams. The U.S. Olympic Training Center, for instance, has a fleet of the machines. The initial WattBike had a large resistance dial akin to a gym bike. The Atom features shift buttons that work in linear fashion, with 22 virtual gears, not like a replication of Shimano or SRAM shifters. WattBike has integrated with Zwift so when you shift you can see the gear change briefly on screen, which is nice, but the gear changes themselves feel a bit vague compared to the crisp shifts on the Wahoo Kickr Bike and the Tacx Neo.

The Atom’s stability is excellent, even under hard sprints. Adjustability is good but not always easy; hash marks make the fit trackable, but some adjustment like stem length requires Allen keys instead of a simple dial like other bikes. The saddle fore/aft is the worst, requiring users to loosen the saddle rails enough to tilt the saddle up before accessing the fore/aft bolt.

Another downside is the single, 170mm crank length, which is ideal for trackies and some shorter riders but not necessarily the rest of us.

StagesBike | $2,899

Pros: Excellent stability, best-in-class frame clearance and easy adjustment, integrated tablet holder, tray and USB chargers

Cons: Shift feel is vague compared to Wahoo and Tacx, no gear indicator

Before Stages launched as a power meter company in 2012, the team behind the technology had been working in the indoor market, both designing indoor bikes for national gym chains but also the power-measuring technology. So in some ways the company had a leg up on the competition for building a smart bike. 

In terms of stability, the StagesBike is rock solid and yet easy to wheel around. The smartphone pad and tablet holder are handy for indoor riding, as are the two USB charging ports, and two water bottle holders.

Stages has the best frame clearance of the four bikes, thanks to the seat tube design that sits behind the rider instead of between the legs.

Similar to the WattBike Atom, the StagesBikes has shift buttons that operate sequentially and do not mimic standard outdoor shifting. Gear indication in Zwift isn’t available yet, but is coming, we’re told.

Tacx Neo Bike | $3,199

Pros: Surface treatments, realistic shift feel, integrated computer with gear indicator, good stability

Cons: Short, wide frame causes rub at many riders’ legs and cockpit too short for some riders

The Neo Bike was the first smart bike, launched at the 2018 Eurobike trade show. With a long history in trainers and smart trainers, Tacx brought a few cool things to bear in the bike, namely surface treatments that replicate rough surfaces with micro stutters in the electronic brake, outdoor-bike-like shifting, an integrated dashboard with a gear indicator and basic training metrics, and the ability to work with or without being plugged into the wall. 

The base of the Neo Bike is stable, but the cockpit extension of the little shelf and tablet holder can wiggle a bit when you’re really wrenching on the bars. Two little fans engage when you’re pedaling, but they don’t really cool you off.

The main bummer of the Neo Bike is the frame; at 6cm wide, the seat tube rubs the inside of many riders’ legs, and the saddle support beam can also chafe. Finally, the bar’s fully forward position may not be stretched out enough for some riders. For example, I came up 1cm short in trying to replicate my position on a 56cm bike with a 120mm stem.

Wahoo Kickr Bike | $3,499

Pros: Best-in-class shifters for function and ergonomics, unique +20/-15 interactive tilt feature, forgiving ERG interactivity

Cons: Least stable and most expensive of the bunch

At the cost of a good outdoor bike, the Kickr Bike is the only one on the market to offer automatic elevation changes to mimic gradient undulations on Zwift courses. The bike tips from -15% up to 20%, and can also be adjusted manually with buttons on the tops of the levers, which are best in class in terms of feel and function. You can program the buttons to operate like Shimano, SRAM, or Campagnolo electronic shifters. As with the Tacx Neo, shifting feels crisp.

Clearly benefiting from years of working with Zwift, Wahoo delivers excellent interactive resistance with the Kickr Bike. Like the Kickr smart trainers, the Kickr Bike will hold resistance eerily smoothly (okay, there is a smoothing algorithm employed here) during workouts. But better than the Kickr, the Kickr Bike is more forgiving when you fall behind on your cadence when doing a workout. Some smart trainers will essentially seize up on you, as they take the ‘power=rpm x torque’ formula very literally. The Kickr Bike will quickly back off when you start to flail, then allow you to get back on top of the gear before it re-engages. 

Similarly, ride feel when free riding or racing inside Zwift is smooth and predictable.

The main downside to the Kickr Bike – beside the price – is that it is the least stable of the four smart bikes. You’re not going to knock the thing over, but it’s not too hard to initiate a little rock. Also, there is only a single bottle cage and, due to the moving nature of the bike, nowhere to put your tablet or phone.

Bottom line: The Kickr Bike and the StagesBike are my favorites

None of these smart bikes are inexpensive, but all are good training tools that integrate well with Zwift. If I were to buy one, I would go with either the StagesBike or the Kickr Bike.

The StagesBike has most user-friendly construction in that it is easy to set up, has great stability, doesn’t even have the possibility of rubbing anyone’s legs, and gives you sturdy places to put and charge your tablet and phone. Power measurement is reliable, and the ERG mode keeps you on track for structured workouts but is forgiving.

The Wahoo Kickr Bike is the coolest, most engaging option because of the interactive tilt, the best-in-class shifters, and the overall feel of the bike when using it for free riding and ERG training. Just be aware that you could get a little wobble when sprinting.