For the rider wanting a more simplified introduction to the world of direct drive trainers, the Flux is the perfect choice. Out of the box the simple set up and easy to use smartphone app enable simple control of the smooth, powered resistance unit. Interactivity and realistic resistance changes with third party software such as Zwift really allow the Flux to shine.
Realistic ride feel
Very stable and quiet
Simple connectivity with third party devices/software
Needs external power
By James Bracey
The Tacx Flux Smart is the second in a duet of direct drive trainers from Tacx. Following on from the all-singing Tacx Neo Smart, the indoor trainer giant has managed to package up the benefits of direct drive into a very competitively priced trainer.
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Out of the box the Tacx Flux Smart needed minimal assembly; just slot the stabilising legs into the main body and bolt in place. Unlike the Neo however, the Flux doesn’t have the convenience of being able to fold away for storage. Ideally it is suited to a dedicated training room or space, as once it is built the sheer weight and bulk makes it difficult to practically move regularly.
Further compounding the immovability is the lack of a carry handle or even basic hand holds, making carrying awkward. Something I feel Tacx has forgotten, as main rival Wahoo has included one on its excellent Kickr turbo trainer. Fortunately for any non-cycling members of the household, the Flux is relatively discreet and good looking (for a turbo trainer), so shouldn’t encroach too much within a multi-purpose room.
Tacx has fitted the Flux with Edco’s MultiSys freehub body, allowing Shimano, SRAM and Campagnolo cassettes to be fitted to the same unit. This also means that if you are a serious high mileage indoor rider, spare bodies can be relatively easy to source. Edco also uses decent sealed bearings for reliable performance. Spacers for fitting 9 and 10-speed cassettes are supplied along with multiple lockring options.
At this moment the Tacx Flux Smart is only configured for use with standard quick release (so not thru-axle) frame configurations. Tacx supplies spacers to allow 135mm (MTB/CX) axle spacing as well as standard 130mm road axle fitment.
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Like the majority of Smart trainers, the Tacx Flux Smart relies on electromagnets to adjust resistance. This means that a power source needs to be available to run the unit properly.
The Flux is capable of delivering up to 1500 watts of resistance for sprint sessions and can consistently hold up to 850 watts for a minute and up to 450 watts for a 20 minute period. Whilst these figures are lower than the stated capabilities of the more expensive Neo, they are more than sufficient to cover the requirements of all but the most powerful riders out there.
To start accessing the features of the Flux, the minimum that is required is the Tacx Training app. Through your smartphone and via Bluetooth you are able to record training sessions and manually control Slope and Power settings. Compatible heart rate straps can also connected.
The only downside to the app is workouts cannot be synced directly to Training Peaks or Strava. If this is important to you, the Flux can be connected to a Garmin or other ANT+/Bluetooth headunit to store data.
But it is pedalling where the Flux really shows the benefits of direct drive turbos and why they are becoming the future of indoor training. Resistance is consistently delivered and feels silky smooth through the pedals. In comparison to a wheel driven trainer, powerful starting efforts rarely feel like they are overloading the motor and the feedback is instantaneous.
Adjusting power manually results in noticeable increases in resistance that read similarly to measurements recorded using different power meters. The figures were always within the +/- 5% stated by Tacx, albeit a little low on most occasions.
The Tacx Flux Smart can be adjusted to apply resistances equal to a 10% climb which is good for most hill training but lacks the 25% capability of the Neo for true mountain goat wannabees. It doesn’t feel quite so natural and ‘bike-like’ as the Neo or Wahoo Kickr due to the lack of motor driven freewheeling capability, but is certainly better than most high end wheel driven trainers.
As with most other direct drive trainers, the Flux produces very minimal noise, even during sustained hard efforts. Testing this by setting it up in a bedroom produced a noise no more disruptive than a dishwasher heard through several closed doors.
For more involved training, Tacx has enabled the Flux to be compatible not only with its own proprietary training software but also with third party software such as Trainer Road and Zwift. Whilst all require more monetary outlay, the ability to create a more immersive VR style experience adds an immense positive to what can be a very mind-numbing experience.
Tacx has a huge range of Real Life and computer generated courses enabling real-time riding experiences of some of the most iconic climbs and races of the world. All of which allow the Flux to adjust resistance according to the situation. Zwift and the more ‘serious’ Trainer Road can be utilised properly, although the occasional resistance lag can be detected on very rolling courses or rapidly changing interval settings.
The only thing to note about the Flux (and direct drive trainers in general) is full-on, out of the saddle sprints can sometimes feel like they are placing additional stresses onto your bike frame. Also, if you wrench on the bars a lot, make sure the quick release is done up tightly!
Overall, Tacx has created a highly competitive entry to the direct drive market with the Flux. Whilst it doesn’t offer the same life-like feel as the Neo, or the same levels of resistance – at £500 cheaper this is something you could live with. As a trainer, the Flux makes following and completing specific workouts and training plans much simpler. For experiencing the proper feel of Tacx’s own VR videos and software and for Zwift users the Flux Smart is an excellent choice, helping minimise the inevitable lack of motivation during indoor training.
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