Support for Tacx older smart trainers

(L Read) #1

The number of owners of Tacx’s older “smart” trainers ( such as Flow, I-Magic, Fortius) probably number in the thousands. These people could become instant customers for Zwift if only they were compatible.

If an older VR software like Netathlon is compatible with these trainers, why not Zwift? These trainers have a wired USB connection to the PC. I believe their communication protocols are already available since Netathlon is supporting them. Seems like this would be some low hanging fruits for the Zwift guys.

(Marco Heikamp DRIVO) #2

Great idea!!  I would love to connect my Tacx iFlow by wired USB connection so I can use Zwift to it’s fullest.  

I agree that there would be thousands instant users ready to use Zwift if this can be made possibel

(Eric C. (Zwift HQ)) #3

Hi L Read,

Tacx have requested you direct all compatibility questions to their support team. The main issue is that we do not have access to the data that is being transmitted by those trainers which is why they are not yet compatible with Zwift.


(L Read) #4

I get the feeling Tacx is reluctant to release the communication protocols for their older trainers for fear that this will cannibalize sales of their newer wireless units.

everone talks about ant+ and Bluetooth but wired is actually more reliable with pc  communication. 

I have emailed Tacx , but got a canned response. Too focused on wireless.

i really think the comm protocols could likely be easily reverse engineered or borrowed from Netahlon software since it already works with Tacx flow and Fortius. 

(Peter Chan) #5

Add me to the list of people wanting support for older trainers - if you could call it old, considering I bought me iFlow christmas 2014. 

I got excited seeing TacX supporting Zwift with their newer trainers. Clearly not the case for older products, but I’m hoping that will change. 

Might see if the people at NetAthlon can shed any light - although, I’m sure they would keep their trade secrets tightly locked away. 

(Howard Markham) #6

Yip, I just bought the TACX Flow off Amazon and will be setting it up soon. I hope that a solution to sync the electrobrake to the Zwift VR will become a reality in the not too distant future. It would be great.

(Micha Will) #7

Here we go, I also need Support for my Ironman T2050 Smart Trainer.


Thanks so far

(Micha Will) #8

Ok here’s the answer from tacx (the needed three days for this one)


"Hello Micha

This is not possible. Only the Smart version is possible to connect to Zwift

Kind Regards,

Tacx Support"



(Eric C. (Zwift HQ)) #9

Yup. Any TACX trainer without the SMART addendum to their name will not work with Zwift as a Smart Trainer.

(Micha Will) #10

Would it be possible if tacx opens their protocoll for you, or won’t there any activity even if its possible to reach those trainers?

(Peter Chan) #11

Zwift only Uses ANT+, and I think all the new smart trainers do too. 

So it would come down to either getting a new head unit that plugs into the motor, to communicate as ant+, zwift allowing usb input + modifying the same inputs, like the other app netathlon that accepts the legacy TacX (an app not made by TacX) or having a driver to emulate spoof an ant+ dongle that accepts the USB I/O. 

(Stian Maurstad) #12


I would also love to use my Tacx Fortius trainer.
It isn´t that old and it´s insane that this huge portion of trainers and potential customers are left with the only option to buy a new smart trainer. It´s quite expensive.

Really hope someone comes up with a solution to this. Winter is here. We need this now!

Br. Stian

(Eric C. (Zwift HQ)) #13

If Tacx decides to open their protocol, we should be able to take advantage of these trainers. But that decision is not up to us.

(. Joi Gudni) #14

I think it´s a question of everyone that has these trainers send Tacx a message and hope that i´ll get heard… i actually bought the flow recently thinking it would work on zwift and that was the only reason if went for it. Guessing if nothing happens soon from them i´ll switch over to bkool or something similar…

(Sylvain Lareau) #15

Golden Cheetah is an open source program that support Tacx Fortius tainer.  Source code is available.

I suppose that the same code could be used in Zwift…


(. Joost PACK) #16

When I started with Zwift I used a Tacx Flow (classic). Turned out that worked just fine by selecting the Tacx Blue Motion classic trainer in Zwift and setting the resistance level on the Tacx Flow computer to 3. The watts in Zwift matched the watts on the Tacx Flow computer very well.

Since a week I have a new Tacx Flow smart, which is much more realistic because Zwift can now controll the resistance.

(Bruce Law UCI 66) #17

Like Trainerroad, I think Zwift could take powermeter data from say Powertap or Vector, and interpolate a power curve for machines such as the Tacx Flow.

Of course it would be passive and not provide resistance feedback, but would offer users of currently un-supported trainers with a power profile to use with Zwift.

The information provided by Joost van der Linde is funtional.

(* ADZ*Minyana NEO) #18

Also I have the Tacx Fortius and have fun with.
It’s a shame that Zwift not work with usb Fortius.

(Bruce Law UCI 66) #19

From Eric C., Zwift, 

“Tacx have requested you direct all compatibility questions to their support team. The main issue is that we do not have access to the data that is being transmitted by those trainers which is why they are not yet compatible with Zwift.”

This is true, but there are solutions.

Trainer Road supports the Tacx trainers mentioned in this thread. How, Zwift may ask? Fairly simple. They used power data from the TR community, generated with Direct Force Power Meters (DFPM) up a power ramp while riding on unsupported trainers. Pretty simple, take an average of the samples and, voila! 

Or easier still, interpolate power data from the work already done by Power Curve Sensor, Here there are Tacx Flow curves for Slope 3 and 7. as well as curves for Blue Matic, Blue Motion, Blue Twist, among others, as well as other brands. 

Now, I have to admit, they don’t provide the algorithm for these trainers, but I think the curves provide enough data points to be able to use them for the purpose at hand. A third plot would be better.

The differences between the different generations of Flow, and other Tacx models, has little, if any, bearing on the performance of the brake.

For trainers like the Fortius, legacy Bushido and Genius it would be more difficult because they don’t use a few discreet curves (settings).

A third, inexpensive option under US$100, may be for Zwift buy a Power Curve Sensor kit and do some testing.

Tacx Flow users - in the connect window of Zwift, choose classic trainers, Tacx Blue Motion Setting 4 and set your Flow to Slope +3. Nearly identical curves, within about 1.25%, close enough to call accurate and repeatable.

In summary, if one has an ANT+ DFPM, they would likely connect that to Zwift. But, it is possible to summon help from the community to compile data for unsupported trainers.




(Ricardo Gonzalez) #20

Heres a response from Tacx regarding older trainers and Zwift.

Hi Ricardo, there is no solution for it, You traiier is not ANT+based, and we cannot control Zwift in this. We are sorry but it is just not possible