Output dropping

Hi , I am relatively new to Zwift, maybe a couple a months, up until a few weeks ago it was great but all of a sudden my output wattage seems to have dropped by about a third, my ftp was at 262 but could easily push 300watts for some of the shorter races, now I struggle to get to 300watts let alone maintain it for more than a few minutes. I have a tacx entry smart trainer and use it on an iPhone. Any help greatly received!

Which Tacx Trainer and have you calibrated it with the Tacx App?

Vortex and yes it’s calibrated using the tacx app,

Are you using a trainer tire?

What PSI is your tire at?

Yeah, a Halfords own one and about 100psi

This seems odd.

This seems closer to reality.

For reference, my FTP is around 255 and trying to hold 300 watts for over a minute is very difficult.


Do you have any insight?

If these images work they are two different days of Emily’s short mix, it’s clear the difference in efforts

Have you considered you may be over-training? If that’s the case, you need to get off the gas sometimes… (as in “rest days are important” :slight_smile: )

Just my $0.02 …

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That is a possibility, but pretty sure it’s computer issue not a fitness issue.

When do you think it occurred? Zwift only really updates every month.

The begining of May is my best estimate, The race on the 5th it was inpacted by the issue abd its been like it since.

30th april race was ok so in that time frame

Game update was 29 April, then a patch on 30th but iPhone takes longer to get updates so it may be related to the game update.

Feel free to contact support but They will take weeks to get to you and might not be much help.

Have you checked you are still got the correct trainer selected in game (sometimes people accidentally change them) with the correct wheel size?

As a stretch I’d suggest trying zwift on another device if you have one.

But this may just be the new normal for you.

Thanks it looks like my tyre size has changed to 700 x 25 but I’m unsung 700 x 23, can’t believe that would make that much difference. I’ll try a different device and see how that turns out.