Use Zwift possible with an old Tacx Fortius but with a Stages Power Meter?



Can I use Zwift on a Tacx Fortius Trainer, a garmin ANT dongle and a Stages Power meter?


Thank you for the info




Yes. If you have a power meter then you can use any trainer or set of rollers :slight_smile:

How does ZwiFt communicates with the Fortius to put more resistance? The Fortius doesn’t support ANT. I don’t want to buy an ANT stick without knowing for sure that my fortius and stages powermeter will work 100% on Zwift. Sorry for the difficult questions.

My NEW Ultegra 6800 STAGE power meter didn’t connect to programm.

My bike in 3-4 fit from desktop, but no connecting, HRS, BONTRAGER CADENCE & SPEED Sensors great works, but not STAGE.

On the GARMIN 810 no problebs everything works fine.


Eric MB you know sicret how I can use my STAGE. Please!!!

@_TempoMapsRider … I’ve ordered a Garmin ANT dongle on amazon so when it arrives I’m gonna try riding the Zwift Island with my PC / Bike with Stages SRAM powermeter / Tacx Fortius. 
I’ll let you know how it works out.




@ _ TemoMapsRider_


I’ve received my ANT dongle and tried Zwift and everything works.

My fortius is connected to my old pc with Windows XP.
Zwift is installed on my Surface Pro (windows tablet/pc) with the ANT dongle attached. So I use 2 pc’s!

When I start Zwift he asks what setup I have. 
I choose for power.

Zwift searches for my Power Meter (turn the pedals to active the powermeter), he finds it and then ask’s for a HR and cadence/speed. He find’s that stuff automatically. The last item I can check is my trainer but it’s an old fortius so I don’t check it. The Fortius is also connected to another pc so I won’t work anyway.

So on my old XP pc I start the Tacx software and choose to go for a free ride. Also I choose a Zwift exercise and I can ride. 

When I pedal harder, swift received all the data (power, speed, cadence) by the ANT dongle while the Tacx software received it’s data from the Fortius it self.

Hope this helps you out a bit.

I used basically the same set up as Peter this morning to test out zwift and it work quite well. I only used one computer. I have vector pedals and used the garmin ant+ usb that came with the pedals. I opened up Tacx TTS and set it to free ride in work out mode. I then minimized TTS and opened up Zwift and paired my Vectors, and heart rate. As vectors give both power and cadence I didn’t need to pair my GC10 sensor.

I did 3 laps of the Richmond course. The only issue is there is not feed back as to the slope of the course. Only your speed changes. You look up and realize you are only doing 12 km/hr and then look at the slope indicator and its 11%.

I tried changing the slope in TTS to match the course but it became too much to juggle and just left it at “0” percent. I did find it hard to maintain a higher wattage output  when climbing compared to real life. For me in real life I can maintain a higher wattage output on a 5% climb then I can on the flats with a lower perceived effort. I think it has to do with a lower cadence and using bigger muscle groups when you are climbing. 

Now I’m tempted to look at a new trainer that would provide the more realistic feed back of changing resistance…I think the companies that make controlable trainers should give a kick back to Zwift…lol

hi Gordon,


The speed on the climbs drops but that’s normal.
The Tacx fortius can’t communicatie with Zwift so no resistance is added.
If you want to climb faster you have to push harder.
I follow you that it’s easier to climb in real life then virtual in Zwift but maybe you gonna get used to it.

I myself use Zwift mostly for a groupride or to follow the workout’s.
With these workouts you have to stay in a certain wattagge and that’s much easier then outside. 
Outsised you have wind, temperature, road conditions. 

If you want a smart Trainer then the cheapest I can find is the Tacx Vortex Smart which i can buy for 325€. With that traniner you get resistance while climbing. (a buddy of mine has bought one)


I have the Tacx Fortius and a stages power meter… I’ve found that doing a free ride with gradient set at about 1-2 % and just shifting into a harder gear to simulate a climb works pretty well.


Is it possible to run the TTS and Zwift on the same computer simultaneously? I have TTS 3.4, is there a free ride mode, I’ve never noticed that?

I use them simultanously. First of all I  calibrate with the Tacx software and afterwards I start Zwift up. After calibration (around 0) just leave the tacx programm like it is. Yes you can also choose a free ride but that’s not necessary.  I run the programme’s both because otherwise the motorbrake won’t work!


Guys I have another question. Is it necessary to calibrate the Fortius before Zwifting with a external powermeter (stages, vector, … ) ? If so what number do you use to ride? 

Peter (EZR-LEAD), I don’t know if you have to, but I do. I calibrate the brake as usual to 0, and then I run a free cycle, slope/time catalyst training routine. In the slope/time free cycle I select 0% slope. I then minimize TTS, and run Zwift.

Oops Peter, I didn’t look back, you were the one that told me that.

I ask because my sister also used the Fortius to train on Zwift.
She rides with an ANT speedsensor and when the calibration is a bit of it’s eather a lot easier or difficult to get certain wattages. 

Also when you calibrate you get a number say 0.

When you calibrate again (without making any changes) the numbers drop every time lower & lower. Find this awkward. 


When I ride with my powermeter I just try to set it between -1 and 1 but I don’t this has much impact on Zwift because Zwift uses my power data and not the speed of my wheel (ANT speed sensor).


Sorry for the spelling errors … keyboard/battery issues


You can operate a Tacx Fortius / I-Magic as a smart resistance trainer on Zwift if you own two ANT+ USB dongles in conjunction with the following software: