Tacx Flux 2 and Flux S Compared
The $150 price difference explained.
With almost everybody stuck at home, all eyes are on trainers. When you’re new to this, there might be too many options. So in this article I’ll simply explain the differences between the Flux 2 and Flux S so you can decide which is best suitable for you. It’s not a big difference, so we’ll be ready quickly.
While the outside doesn’t really matter because the Flux series is almost identical. The only thing you’ll have to do is assemble the legs get get going. But here is a side by side compare. The Tacx Flux S on the left and Flux 2 on the right. The only notable difference is the S is a 2 and the feet are Tacx Blue on the Flux 2.
Tacx Flux S 
Tacx Flux 2
In Numbers
Because the form factor, the experiences are almost identical, the real difference lies in the numbers. The best way to compare this is always a table, and then I’ll explain later for the differences why or when they matter.
| Flux S | Flux 2 | |
|---|---|---|
| Max power | 1500 watt | 2000 watt |
| Max incline | 10% | 16% |
| Max torque | 22.1 Nm | 41 Nm |
| Max brake force | 120 N | 65N |
| Accuracy | <3% | <2.5% |
| Fly Wheel | 15.4 lbs (7 kg) | 16.8 lbs (7.6 kg) |
| Mass Inertia | 50.3 lbs (22.8 kg) | 68.8 lbs (31.2 kg) |
Wattage
The Flux 2 has a max wattage of 2000. That number is enough for a professional, maybe not Chris Hoy.. but should definitely be enough for you. Now, many years ago, I could put out about 1600 Watts. But I’m a big guy (6’6 & 195lbs) and I rode a lot. So the Flux S would not have been sufficient. However! This was my 1 second absolute peak. Not something you’d see me do daily. I pushed this out during a test on a wattbike. I also died about three times during that test. So for me, the S would be enough for training.
Incline
The max incline on the S is a bit low. Compaired to the Flux 2 and the competition. If you really want to train for some serious climbing it can fall short. As for reference, here are some well know climbs and their steepest bits:
- Mont Ventoux 10.8%
- Box hill 12%
- Stelvio 12%
While these numbers seem impressive, it doesn’t mean you can actually achieve this. Because one issue with trainers is that they actually don’t do 10% when Zwift says 10%, it’s less. And another factor is the minumum wattage a trainer can give. The Wattage floor lies somewhere at ~100 for the Flux S and ~90 for the Flux 2. For an entry level trainer, the S will be fine for you.
Noise
In terms of the noise produced, these trainers are not the quietest. If you are looking for something ‘silent’ then have a look at the KICKR Core or Neo 2T. In terms of sound difference between the Flux trainers, the Flux 2 is slightly quieter. To hear a comparison it’s best to have a look at DC Rainmakers video.
Fly Wheel Weight & Inertia
One big factor in ‘road feel’ is the fly wheel weight. Generally speaking, the heavier the better. But this doesn’t really work like this for the Flux trainers. Both give a good road feel for the mid-range price segment, with a slightly better experience on the Flux 2. Which makes sense as its fly wheel is heavier.
Zwift
Both trainers send your speed, cadence and power over bluetooth and therefore, there is no difference in using either for Zwift, apart from their technical capabilities, noise, etc.
Conclusion
If you are looking for an affordable trainer but want something that can fold up a bit more, maybe think of Wahoo KICKR Core which is quieter than the Flux 2, had more connectivity, but a slightly lower max wattage (1800) and goes for the same price as the Flux 2. But looking at the Flux S, that’s a very good entry level trainer and the Flux 2 a mid-level and Tacx includes 142mm & 148mm adapters with the Flux 2.
Prices
That’s about it. If you have any questions or comments, drop them below!
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