Hello zwift buddies,
Yesterday I did Stage 2 of Watopia’s tour, a group ride of over 1400 riders, 28 km for 100 m of elevation gain in C category. I finish this ride on 41st place, and those who rode next to me seem to have similar average power after the ride. Surprisingly, by the end of the ride my FTP increased from 199 watts to 248 watts, which equals 4w/kg according to my weight of 62 kg. I am a woman with an average level in cycling, and I find these numbers a bit exaggerated. However, on my last 3 races on Zwift Power I had an average power of 207 w, 210 w and 218 w on efforts of 10 to 20 km (less than 20 mins). I used a smartrainer Elite Direto that I’ve been using for months and never had this issue. Any idea of how this situation can be explained ? Is it a zwift bug, a trainer calibration issue, or my power really increased overnight?
Thanks for your help!
I’m sorry to say that I don’t think your power has increased overnight. Your ZwiftPower numbers tell a story:
You have gradually been improving but this ride took your best 20 minute watts from 208 to 248 a 19% increase.
This ride produced new PBs across every time from 15seconds to 20minutes. This is very unlikely and almost certainly caused by a miscalibrated trainer (if only for this one ride - I don’t know if this can happen).
Although being pulled along by a large group might have motivated you to improve by a few Watts it is unlikely to have helped add 40 watts.
Your Average HR and Max HR were both roughly in line with recent race heart rates.
I don’t know enough about calibrating an Elite Direto or updating the firmware so possibly others can offer advice.
[Edit - you might wish to try another ToW group ride, put in a similar HR effort and see what the results provide.
If you find a method to re-calibrate you trainer, or if this ride was a one off you may then wish to contact Zwift or ZwiftPower support to have this ride removed from your record as it will now be affecting your CE and ZP race categories ]
I don’t know much about them either, but the rumors are that the Direto is easily miscalibrated to give you an increase in power. I would assume @D_Florina_TT1D has an issue with the trainer.
You might also wish to read this thread. I’m not sure whether @Steve_Cl can comment further on whether the calibration he performed helped or hindered the long term use of his Direto.
https://forums.zwift.com/t/elite-direto-xr-resistance-problem/589092/2?u=ian_attoe
Thanks a lot for your fast reply on this matter. I will try to recalibrate the trainer and give it another shot on the ToW to see how it goes… I was also thinking of doing a FTP test on zwift to adjust it on my profile. However, I am afraid the last ride drastically changed my ZP race category (from C to B, almost A) which is unrealistic… Once I have the confirmation it was due to a miscalibration, I will try to have the ride removed on ZwiftPower and my power adjusted accordingly.
Do you think it could be because both I and my boyfriend use the same trainer? And his FTP is more around 290 w. 
it shouldn’t matter who uses the trainer, it should be accurate regardless… but unfortunately the Direto is known to have accuracy issues.
Weird it never occurred before and it usually seems quit accurate…maybe the drive belt is worn out
At the time, I ended up using my Direto for a while getting power numbers from my 4iiii, but I also had the issue of the controller was giving very high resistance even at low (but not zero) trainer difficulty… Effectively the 34 chainring with 23/25/27/30/34 sprockets covered my power range, albeit with a minimum of ~150W at ~60rpm cadence (when I much prefer 90-110).
I then found a deal at Rutland Cycles for a Saris H3 for ~£480 around Easter and I’ve used that since, but I’ve still got the semi-broken Direto taking up floor space in the mancave!
Which could prove interesting, because someone recently posted a possible fix link for controller issues on here.
Thanks.
Hope you get your old Direto back up and running.
Hmm, seems like an over-generalisation to me. I’m not aware of a general “accuracy issue” with Diretos. And there are several models of Direto anyway.
just the rumors I’ve heard, and seen a few posts on reddit about it reading high
had a standard direto for close to 21 months and calibration of it (tightening the belt to match the calibration number on the bottom) caused it to read higher than my 4iiii crank at the time, power numbers were 20+ watts higher than the 4iiii sometimes more on longer rides but the highest out it was a crit where i apparently did 4.7wkg which is way out.
it developed a really bad noise so it went back under warranty and was replaced by a neo 2t which i have found to be far more accurate
Here are some updates from yesterday :
I’ve checked the calibration with the Elite app and everything seemed to be in order: no miscalibration, no error, no awaiting update.
I’ve done the 20 mins FTP test, and it turned out to be 194 watts, which seems closer to the reality than the other day. That wattage increase remains a mystery…
There are some rumour that go in the same way for wahoo’s trainers… For the price I paid the Direto when it was launched, around €800, it better be accurate. 
I’m pretty sure that for any trainer model we can find anecdotes suggesting that they are inaccurate/unreliable/junk.
i’ve had a saris, a direto x (two), and now on a kickr v5 and they all read about the same. the saris needed calibrating pretty much every ride though
what was your average heart rate for that FTP test vs the event?
stage 2 event can be pretty spicy so if feeling competitive = bigger numbers (but probably not that big!)
did you connect the trainer to the same device you typically use?
had you taken the bike off/on the trainer since it was last calibrated and doing this event? or when was it last calibrated?
I have an old skool Elite Direto from 2019 and it still reads at roughly +/- 3-5% compared to Vector3 dual sided pedals despite taking a hammering over the years…!
has he ridden it whilst logged into your account? cos that will affect ur FTP.
Average HR for the ftp test: 168 vs the event: 184. I used the same device as usual. But the last calibration was the day before, and I took off my bike in between. 