I would like virtual power. Will you add it? (COMPLETED)


I’ve tested the app both in web and my android device. Looks good and impressed, but I don’t have a power meter or a smart trainer. Just an Elite trainer with a plain simple speed/cadence sensor…

Do you intend to add virtual power?

I guess I’m not the only one with such a setup :slight_smile:

Can you connect the speed and cadence sensor to your bike computer? If it broadcasts a signal (and is not Ant+ only), I guess there could be done something with that.

Otherwise, how?

Other than that, as the purpose of TrainerDay is to build (power based) workouts or training plans, how would you be able to follow one?

Maybe @Alex can correct me - he usually does :joy:

I read ‘virtual speed’ for some reason…

Today we do not support virtual power. This is the first request I have seen for that (I just created new topic for this and turned it into a feature request so people can vote on it). If there was enough demand I would consider it but we don’t have it today and seems unlikely for this winter. Also we don’t support Ant+ now so we would probably need that first for many riders that would like this feature. Sorry I don’t have better news…

@Alex thanks for your prompt reply :slight_smile:

glad that you added as a feature request to be voted.

Since I come from the software development world, I understand that not everything can be added day 1 on an new app.

So, It’s better to start as you did already, with a stable app and then build on it :wink:

hi @Cyclopaat

I can connect my speed/cadence sensor without issue … my sensor supports both bluetooth and Ant+ …

the case is as Alex replied, that “Virtual power” is not yet a supported functionality in the app

Yeah, as stated later, for some reason I read ‘virtual speed’…

I should probably vote for this, to atone for my stupidity, but @Alex already knows I have a Neo 2T :sweat_smile:


Would be nice to have!

Virtual power is interesting… I used to use it for years before I got my power meter.

I was thinking of creating a device to turn speed and cadence sensor data into an ANT+ or bluetooth power meter signal - this would mean you could use it with anything… I think it’d be relatively low cost to make and could be adjustable - eg you could calibrate it against real power to get an accurate reading or just adjust it manually.

I wonder if there’s any demand for such a thing… Off the turbo trainer it’d be useless due to too many variables, but on the trainer it’d be pretty accurate I think… the only variables there (after calibration) would be heat really (as the trainer and tyre warm up their efficency will change…) but you could actually compensate for that too…

There must have been some demand because I believe TrainerRoad built it (a long time ago I believe) but I would guess that demand continually goes down as people give up and buy some type of device to measure power.

does that mean that perhaps you will not add it in the future?

Very recently, I am realizing more and more how valuable this is. I have changed my view and feel that people training with virtual power are very much the people we want to support so yes. I am going to do everything possible to get it “soon.” My guess is that will be mid-2021. First we need to continue to improve performance and stability. It’s stable now for 90% of the riders but I really want to get it solid first. It could be as early as 3-4 months from now. I have had a huge number of requests for ANT+ so I believe that needs to come first.


I used virtual power when i started with zwift and trainer road. I think trainer road had my century fluid trainer. I think you need all of the trainers to compute their virtual power. Looks like a long process. You need to create a power curve for each brand/model of trainer.
Zwift did not have my trainer so i picked a generic one but not sure on how accurate it was.

Oh my… I have not looked at this at all. Thank you for the insight… Yeah if it can’t be done in a reasonable quality fairly simplistic way then it might be too much for us but hopefully we can find a reasonable solution.

Yes this is correct, it’s a calculation of the fluid resistance from every trainer (at X speed sensor speed, how much resistance is X trainer putting out – and then converted into power). I don’t think the trainer companies give much information on this, pretty sure it was all done manually by the companies using virtual power, if I remember right

Golden Cheetah has Virtual Power and it‘s open source. Maybe you can get the power curves from them if you ask nicely.

Oh interesting. I am friends with Mark at GC thanks for the tip. Yeah I see some stuff in their code but looks pretty complicated. When the time comes to look at this more deeply I will reach out to him. He’s a funny guy in that he only responds to stuff he is really interested in but he has helped me.

Back in the days, VeloReality had most dumb trainers covered. When a trainer was selected, the formula for speed to power conversion was shown for every resistance setting. You could even add your own unsupported trainer. Accuracy is not very good, but as long as it is stable, you can use it for training. Just don’t compare with other athletes.

I like this idea. More and more I was thinking that this was just too much work for us but actually doing it that way makes it more feasable. They could connect to Strava or upload a max effort GPX/TCX file from outdoor to estimate their ball park FTP and then with a ramp test in the app we could set their virtual FTP and resistance… or something like this. Needs more thought but interesting ideas. Keep them coming. These insights are great.

Virtual power through cadence/speed would be awesome.