Are there some 'boosting' coefficient for women in zwift? Some discrepancies between FTP in Zwif and ZwiftPower

Hello, I’m a zwift (and smart trainers) newbie but not a newbie at all in endurance sports so I got some problems in comprehending how things work in zwift and why are there some strange results. If you can help to clarify them I would really appreciate it.

To begin:

  • I use Tacx Neo
  • Zwift is installed on Iphone (still can’t install zwift on pc. The problem is similar to Zwift Doesn't Launch (Windows 10) - and that guy was able to solve it only with reinstalling Windows)

We use this Tacx Neo (and this Iphone with installed Zwift) together with my girlfriend - one at a time of course. She has her separate account on Zwift (set up to 60 kilos) and I have my own account (set up to 100 kilos). I got this Tacx Neo from my friend who weights around 80 kilos. I didn’t do any additional actions, except of pairing it with Zwift.

So, I install zwift and went on zwifting. No “wrench” for calibrating ever appeared next to pairing devices - it’s still the case after like 6 hours of riding (so, 12 hours total for 2 persons).
And now to problems:

  1. We went for Virtual TDF - l’Etape du Tour and for Discovery Rides - and in both rides the time of my girlfriend is better than mine :slight_smile: and it’s not like I didn’t try - I went for sure on my Anaerobic Threshold and most likely I suffered even more than her (When I was 10+ kilograms lighter I used to be semiprofessional cross-country skier, competed in NCAA First Division and also I had some positive experience in amateur cycling races). Actually I would be happy if she would be stronger than me in real life since I’m kind of coaching her to triathlon competitions with some serious amateur goals but we both know that’s she is not there yet: even on tough (long and steep) uphills which is her strongest part she is little bit slower than me on a real road not to mention flats and downhills. So, here is the first question - are there any chance that Zwift calculate speed for male and female zwifters differently? Or what can be the reason? As a side note I would add that I’ve lost about 15 minutes to the buddy of mine whom I know very well and to whom I would lose about 5-7 minutes in a real life on a mountains course like that Virtual TDF (and whom I would very likely beat on a flat or even slightly hilly road race, if everything went normal)

  2. About FTP numbers. First of all, when I do some 20-minutes Effort on a street (without any powermeter though) Strava estimate my output as 3,4-3,5 watts/kg - about 340-350 watts. Judging by speed and my results I believe this can be true and quite accurate estimation. But in Zwift right now I have my calculated FTP for 20 minutes as 214 watts (2,1 w/kg). In the same time, Zwift Power somehow calculate my FTP as 300 watts (3 w/kg) - this seems way more reasonable, I’m not in the best shape right now, obviously - but how this discrepancy have occured? And anyway, in zwift rides my speed is more like 2,1 w/kg). My girlfriend has about 3 wt/kg on zwift - this seems about right or maybe little bit flattering (and she as not set up an account at zwiftpower yet). Is it possible to think that maybe my results on zwift were somehow lowered? - I don’t know, maybe there are some calibration issues?

  3. As a told eatlier there is no “wrench” icon when I’m pairng devices so I can’t calibrate and spindown it. But what I have noticed, that I can ride (with no anaerobic efforts) on 53-25 gear to 13% climb - there is no way I would do it in real life, except of the uphill finish sprint. In the same time, I can easily spin 53-12 and on a cadence of 90 my speed is quite modest. In order to accelerate to 700-800 watts I have to spin it like crazy with the cadence of 130-140. And my average cadence on zwift rides is about 95, which is maybe good for frequency and training, but I know that usually my cadence is around 80-85. What should I do to make “wrench” icon to appear and what can be the reason for such a strange feelings about these ftp calculations?

Thank you for attention. I would appreciate any tips/advices/solutions

Hi @Kamehameha_Kamehameh, welcome to the forums.

I don’t think you need to calibrate the tax neo, maybe this is only true with the newest model, the Neo2? I would use the manufacturer app, Tacx app, to calibrate anyway if it is available. Not all trainers can be calibrated within Zwift, and they prefer you to use the manufacturer app anyway.

I don’t think so, speed is measured by power and weight, and height. There are many calculations that go into how your speed is determined. This post will help explain it: How Does Zwift Determine My Speed?

Have you done an FTP test? That would be the best way to know what your true FTP is, don’t use the Strava estimations. I also think you have to manually enter your FTP in ZwiftPower, it doesn’t pull it from Zwift if I recall correctly. Either way, your registered FTP makes no difference in the power you are producing and the speed you are travelling.

Check you “trainer difficulty” setting in the Settings menu while riding in the game. The default is 50%, middle of the sliding scale. Which means that a 13% hill will only feel like a 6.5% hill on the trainer. Moving the slider all the way to the right, 100%, will make the 13% hill feel like a 13% hill. Move it all the way to the left, 0%, and you will get no change in resistance at all, all roads will be flat.


Thank you, Mike!