Garmin Tacx Flux 2 Reviewed

The Garmin Tacx Flux 2 is a smart trainer at an equally smart price.

As winter set upon the Northeast, my opportunities for outdoor cycling quickly dwindled as the forecast started to look more and more gruesome. Temperatures went from the 30s and 40s during the day to teens and single digits in a week. While I’ve got plenty of cold-weather gear, there’s nothing enjoyable to me about the cold penetrating my lobster gloves and having my feet go numb. 

For some, winter is off-season and it’s a time to balance out those oft-neglected upper body muscles. For many cyclists though, winter is the time to switch to indoor riding and to maintain or increase the gains made over the last season. 

But let’s face it, most indoor riding sucks. Stationary trainers are deadly boring, rollers require too much focus (which makes it hard to get lost in a Netflix series), and spin classes don’t translate to real-world bike conditioning. 

There is another option, the “smart trainer.” These interactive trainers provide variable resistance and when paired with a compatible app like Training Peaks, Zwift, Rouvy, BKOOL, Tacx Training (and many others) simulate the conditions of an actual bike ride.  Also see our review of the Direto.

Smart trainers simulate climbs and other riding conditions by continually varying the resistance on the rear wheel, enabling users to climb mountains, draft off other racers, and cruise downhill. 

Even better, smart trainers send ride data back to the apps, with the most important bit of data being power (in Watts). All of the training apps use power to determine the speed and also allow them to tailor specific, individual workouts. 

Watts is the preferred metric for serious bike training as it’s not affected by gear the way speed or cadence is. You’re either putting out the watts on a ride, or you’re not. If a training plan says you should ride a base mile workout for example, without knowing your power output there’s no way to know if you’re overtaxing your body. 

With the built-in power meters in a smart trainer, it’s possible to build and follow complex training programs as consistent as those the pros would follow. (If you have power meter pedals, this info can be tracked as well for more complex post-ride analysis of individual leg output, pedaling deficiencies, and more.)

Smart Vs. Dumb

There are two types of smart trainers—wheel drive and direct drive. Wheel drive connects just like a standard “dumb” trainer, with the rear wheel hooking into the trainer and the tire sitting on a roller. The second type of trainer is the direct drive trainer on which the rider removes their rear wheel and connects the bike to the trainer with a cassette that’s mounted on the trainer. 

Direct drives provide a better experience, as there’s no lost energy in the friction between a wheel and a roller, and they eliminate wear on the rear tire and wheel, so you don’t spend your winter wearing out a single tire out of a pair. 

Get On The Right Tacx

For this winter’s workouts, I purchased a Garmin Tacx Flux 2 which is the company’s middle-tier direct-drive trainer. The Flux 2 has a retail price of $899.99 (on Amazon), while the next model up, the Neo 2T is $1399.99. The Neo 2T allows for rocking the bike to the left and right for a more natural training workout, and the trainer can also simulate different road conditions like gravel or cobbles providing the app you’re using supports road simulation. 

While the side-to-side motion would have been nice, neither that nor the ability to feel like I’m on cobbles made the $500 difference make sense for a casual indoor trainer user like myself at the time. That said, if you’re a hardcore rider looking for the most comfortable and most accurate trainer, splurge for the Neo 2T.

Wait, Wasn’t It Just Tacx?

Garmin acquired Tacx to get into the smart trainer market and brought with them the manufacturing QA that their GPS units are known for. Garmin addressed the existing Tacx issues and has built and/or upgraded a solid line of trainers. 

The original Flux 2 had several problems including measurement (you can read more about that here https://www.dcrainmaker.com/2020/07/tacx-flux-2-smart-trainer-edition-review.html) and Garmin quietly replaced it with a newer version in the middle of 2020, less than a year after purchasing Tacx. Since that mid-2020 refresh, the Flux 2 has been rock solid and reliable.

Out Of The Box, On The Bike

The Tacx Flux 2 setup is painless and quick—simply attach the legs to the body of the trainer then add a cassette and you’re good to go. All the tools you need are included, as are several different types of adapters for different through-axel adapters. 

Since removing my cassette from my current bike was a non-starter I picked up an inexpensive (and heavy) cassette online with the same gear ratio as my road bike. The weight doesn’t matter since the cassette will never spend a moment in the sun, and the $25 price tag was easy enough to swallow. 

Some direct-drive bike trainers come with a cassette, but I personally like the flexibility of being able to swap out cassettes if I want to attach a different bike with different gear ranges. 

The Flux 2 comes with several adapters for through hubs but I opted to put one of my older rim brake bikes with standard quick-release skewers on the trainer.

It took less than 20 minutes to go from the box to attach the bike, though having put cassettes on bikes many times reduced some of the build time you might experience if you’re not familiar with the process. In any case, one should expect to be riding within half an hour. 

As with many smart trainers, the Flux 2 needs AC power, and while the cable they provide is long, it’s not super-long so you’ll want to either be careful with trainer placement or get an extension cord. 

While the rear of the trainer is the natural place for an AC cable from a manufacturing standpoint it’s a bit awkward on a trainer. Most people ride on trainers facing a TV or tablet both of which need to be plugged in. Often riders use fans, and those fans need to be plugged in as well. That means the trainer is facing electrical devices that are plugged in to outlets, so the cord would be more practical in the front. Unless you place your trainer right near a wall with an outlet directly nearby you’re going to end up with a power cord running across your workout space. 

There’s also no power switch on the Flux 2 so if you’d like to turn it off you’ll need to pull the cord. It’s probably using next to no juice when it’s not being ridden, and the Bluetooth radio is probably off while the device is idle, but I’m still partial to being able to turn things off manually at the device. 

Booting Up

The Flux 2 communicates with devices with either Bluetooth or ANT+ (but is controlled via Bluetooth) although for ANT+ data you’ll obviously need an ANT+ capable device for this functionality (like a Garmin Edge bike computer). 

I have had zero problems with Bluetooth connectivity between the Flux 2 and my MacBook Pro, AppleTV, iPad and iPhone during testing. 

I also purchased an ANT+ dongle and a USB cable extension for my MacBook Pro, but as I haven’t had any drops with Bluetooth, the ANT+ dongle doesn’t actually improve anything. For testing purposes though, I can confirm that the Flux 2 and the MacBook Pro work well together with a cheap ANT+ receiver. 

Connecting the Flux 2 to my devices had the usual amount of configuration oddness that any Bluetooth paring process has. There was a few minutes of paring and un-pairing things before I got it to work right since I was both trying to get my devices to work with the trainer and also get Zwift to work with it at the same time. 

Having so many devices that connect to the Flux 2 causes the only initial connection issues. I will occasionally have to turn off Bluetooth on one device while the one I want to use for my workout connects to the Flux, but then after that I can flip Bluetooth back on elsewhere. 

I found the most problematic use to be when my iPhone was paired with the Tacx to use the Zwift Companion app as the communication to the Flux 2. This simply didn’t work well, so I’ve removed the Flux 2 from my iPhone’s Bluetooth device list and now I can connect to my iPad, AppleTV, or MacBook Pro with no issues. To be clear, the iPhone paring issue was more a problem with the Zwift Companion app than the Flux 2. 

Putting It To The Test

I’ve used the Tacx Flux 2 with nearly a dozen cycling apps, and they all work perfectly. I’ve tested it with Zwift, Tacx’s own apps, BKOOL, TrainingPeaks, ROUVY, and more. Every single tool works perfectly and seamlessly with Flux 2. 

The only issues I’ve ever had with it are when doing a calibration test in Zwift, where sometimes after calibration the watts measurements are way off. On my first trip up Zwift’s Alpes du Zwift after calibrating my trainer, my wattage was showing 100 watts during an 11% grade while riding 8 mph (at 180 lbs). If that doesn’t make a lot of sense, just know that’s way off. 

Today I did a calibration after warming up the trainer for the recommended 10 minutes, and the app showed me at 430 watts and 23 mph on the flats while I was barely pedaling. 

Re-calibrating fixed this and since it’s only happened in Zwift I suspect it’s a communication problem. One thing that I’ve noticed is that Zwift tells you to accelerate to 23 mph but at 20 mph instructs the user to stop pedaling. I am guessing that if you follow the instruction to stop instead of finishing hitting 23 mph, it causes calibration issues. 

I have put hundreds of miles and thousands of feet of vertical climbing on the Garmin Tacx Flux 2 and it hasn’t failed on me. I spend a lot of time on Reddit forums for Zwift and the other training apps and I know that there are some other trainers on the market that have problems with strange noises and wobbling. (Since I haven’t tested them personally, I’ll skip calling out the brand as I can’t verify these issues.) This constant stream of complaints about other devices makes me even happier about buying the Tacx. 

Garmin Tacx Flux 2 Yes, It’s Worth Every Penny

It’s very hard to write a review for a device that’s so simple at its core, and that performs without problems. The fact that my biggest issue is the location of the AC power connector should tell you about the value inherent in the design of the Tacx Flux 2. 

Having spent a whole winter on it, the one thing I wish is that I had splurged a bit and gotten the higher-end model, but that’s not for reliability or performance, it’s simply for the ability to get some horizontal motion when riding long training slogs. There might be an upgrade purchase in the future. 

But then again, maybe not. The Garmin Tacx Flux 2 seems built like a tank, and it feels like I could get a good decade of use out of it. It’s a great middle-point between super-expensive and budget-level trainers. 

If you’re looking for an upper-middle-level trainer at a good price point with all the specs you need, you could do no better than the Garmin Tacx Flux 2. 

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