Support for old, non-ANT+ trainers and bikes

(F udgy Pumpkins (B-) kiss) #41

I borrowed a Beagle USB sniffer and watched an entire Zwift init sequence on a new Tacx T2900.  No weight or wind resistance pages are ever sent.


I think what this means is that Zwift are assuming the trainer is set to a default weight, and using slope to change the resistance.  So, if I put in 50kg as weight it might put my slope at 1%, but if I put in 100kg it will put the slope at 2%.  I assume then the slope is reduced when drafting too.

  The reason all this works is because all that Zwift uses is the actual power coming back from the trainer.  It ignores speed etc.  It uses the power reading to calculate speed.    It makes sense because now they don’t have to support different modes for smart trainers, dumb trainers, and dumb trainers with power meters.



(Irnie Eugenio) #42


Your app sounds awesome and would be willing to test out when it is available (I have an older version computrainer).

(Dave Miller) #43

Any updates Paul?

(Kevin Murray) #44

What is involved in getting this working with a Tacx Flow?

I’ve been using antifier, and in erg mode I’ve noticed the power is all over the map at times.

I can do the updates/changes, I just need to know where to start.

(F udgy Pumpkins (B-) kiss) #45

Maybe not much.  Is Tacx Flow supported by Golden Cheetah?  I got some of the connect code from there.  Golden Cheetah didn’t do the power right though, so I used my Powertap hub to create a power profile. This may be different on the Tacx Flow.


First, find out the VID and PID. Go to DeviceManager. Right click the trainer->Properties->Details->Property->Hardware Ids.

You can put those values into fortius_code/LibUsb.h and then in LibUsb.cpp  at line 328.   


If you don’t undertand what to put in the code, I can add the VID/PID but I can’t test it.  Send me the VID PID, I will put them in the code and update the GitHub.  You can update and retry it.

(Dave Miller) #46


Can I assume you either ran into a snag or are unable to release an app this year?

(Dave Miller) #47


As we start to approach the indoor ride season I wanted to reach out one more time to see if you will be releasing the protocol for Tacx I-Magic trainers (and others) to work with Zwift.  If you aren’t, just please let me know and I won’t keep asking.



(Erik Schukking) #48

Dear Paul,


Can you help me to work my Tacx Flow (T2220) to work with Zwift?


Met vriendelijke groeten,