Totally agree with Joe… don’t get me wrong, I love Zwift, really do, but this is going on for ever it seems, that it’s not even funny anymore.
I’m getting new powermeters in tomorrow (Assioma’s) so I’ll try a FTP test again. Hope it doesn’t screw up again this time. We’ll see!
I’ve recently bought a wahoo kickr and had the same problems as others; first time I tried a short FTP test on Zwift, spinning out in hardest gear once 20 min test started and powering only 120 watts.
Tried again today and worked a dream. Not sure if I did anything differently, other than repairing and adjusting Zwift Ran the test in ERG mode and kept cadence high (90-100) during warm up. I could feel resistance changing as target watts increased. Remained in the same gear during the test and could feel resistance changing as power increased in line with increased cadence. Final FTP was 240, which was roughly as expected.
I have the opposite problem. I just did an FTP test last night on a Kickr and the warm up is where I was spinning out. Zwift gave me 0 resistance. When the 20 min FTP started, resistance started and worked all the way through. Any ideas of what went wrong would be greatly appreciated.
I’m SO thankful that I finally found this page. Day 4 with Zwift and Wahoo Kickr and I was about to give up trying to do an ftp test. Let’s hope that I can set the resistance right for an hour! Time for Wahoo to send as a notice in the box with the stand!
Same issue as 90% of Kickr owners - hit ‘freeride’ section of FTP test (or any custom workout with a freeride section), and resistance more or less disappears!!
Otherwise have had no issues with regular rides, group rides / races, or custom workouts ERG mode (without freeride sections). Fully up to date Kickr (Bluetooth), MacBook Pro, Zwift etc etc.
Can’t believe after so many people reporting this issue, over such a long time, that Zwift haven’t come up with a solution yet - Kickr is one of the most popular trainers!!
Has Zwift actually hooked up a Kickr and tried it to see the problem first hand??!?
Will be a massive let down if I have to pay to use TrainerRoad to do a simple FTP test… :-/
Had a similar problem but with slightly different results. My setup is a Cycleops Magnus, purchased directly from Zwift, AppleTV 4K and Zwift mobile link.
I’m a new Zwift user and have pretty much only been using the “Just Ride” mode up until now. It has worked great and I found the changing resistance with terrain to feel fairly accurate. I calibrated the trainer before the test in Rouvy because the calibration never seems to work in Zwift, even though Zwift sells the trainer with that as a listed feature. But that’s a separate issue. Anyway, ERG mode worked fine for the warm up like everyone else, but then all resistance dropped out and I was spinning in 52/11 like I was going downhill. The only difference from most people in the thread is that I saw a huge spike in Wattage… up to 2000. That seems unlikely for a number reasons, not the least of which because the Magnus is suppose to have a max wattage of 1500. I turned off the test because I figured something was off. Maybe I should have seen if the wattage would settle, but it seems insane that I would hit such an insanely high wattage. I think the highest I hit during during a free ride was 600-800 during a Sprint, and I was at max effort, which was not the case when the test started.
I’m left with the question of why is this such a problem? I get that you would need to turn erg mode off for the test, but I’m getting the impression that the trainer then just turns into a “dumb” trainer without any resistance from Zwift? Do I have that right? I guess I’ll see if I can use the increase resistance buttons, but that seems like an analog solution for a “smart” trainer. Why can’t it just switch back to the normal resistance for 0% grade that you get in free ride mode? Or it can give you actual terrain resistance and the user can select a flat route. It’s not as if you can find a perfectly flat route anywhere in the real world. And even if you could, does changing terrain really matter when you’re measuring power threshold as opposed to a PR in a time trial? Couldn’t you in all reality get a similar FTP from a sustained climb as you would from a flat time trial if the effort is the same? The only difference would be the speed which shouldn’t really matter. Am I thinking of FTP correctly? Please someone set me straight if I’m wrong.
Sorry for the rant. The workout tonight was just the nail in the coffin to a $h!t day.
Just had the same issues with Wahoo Kickr Snap and Zwift. From my previous rides my FTP was 241W but when I did the tFTP test to check where I was at I couldn’t get the power above 160W even using the increase power button. Not sure what else to try?
Any ideas please?
Just had the same problem as most others, warm up went fine, got to the Free Ride section and had no resistance. Using Wahoo Kickr Snap with Zwift on iPhone. I’m in the last week of the 4 week FTP Boost program and I feel like I’m wasting my time because I know that the FTP test at the end isn’t going to work.
It would be good if the resistance was set to 1 - 2% gradient, but it is like riding downhill, no resistance.
It’s disappointing that this thread started over 2 years ago and we are still having this problem
I was having similar FTP test problems to the above- Wahoo Kickr Snap, fine on the warmup with ERG on, but then as soon as the actual test started- spinning out with resistance much too low, even after adjusting it to the max possible as zwift advises above
Then I found the beautifully simple solution… do the warmup in the lowest possible gear! Then there’s loads more gears to use after the ERG finishes
Happy now 
An update to the FTP issue, firstly I tried Sven’s fix but it did’t work for me, maybe I changed down gears to close to the FTP test, I don’t know.
Last Sunday I did the Ride Like King Event, a Group workout. At the end of the workout it went from a 205 watt effort into a 14 minute Free Ride (the FTP test is a 20 minute Free Ride) and it worked perfectly, I was doing 220w in the gear I was in, I changed up 2 gears and was able to do 300w, changed up another 2 gears to 360w, it was working perfectly.
Zwift can you please look at how the Ride Like King Free Ride was set up and see if you can replicate this in the FTP Test as it worked ?