Weight and Height Changes in Events Now Locked [March 2022]

Today we are beginning a series of security changes to address an exploit in game where a Zwifter could change their weight while in an activity in an attempt to gain an unfair advantage in competition. This exploit could be detected on Zwift servers, but would be hidden from public view, therefore impacting community racing. The first fix, which is live today, addresses competitive integrity and ensures greater fairness, specifically in events.

What does today’s fix entail?
Starting today, weight and height will remain locked when you are in an event.

If you are in an event and you try to make a change to your weight or height via your zwift.com web profile, you may be presented with a generic error message. If you try on Zwift Companion, changes will not save, and therefore performance in game will not be impacted.

When can I change my height and weight?
You’ll still be able to change your height and weight when you are logged out of the game, or when you are logged in, but not active in an event.

What about the bug bounty program that was mentioned?
We know a lot of you are also interested to hear more about the bug bounty program. This will take time to develop but as with this fix, we will keep you updated as soon as we have news

This is the first step of many we are taking to address game integrity. We look forward to updating you on additional efforts.


Good news, thanks. No intention to reopen previous discussions but personally I’d like to also thank the various parties that have contributed to pushing this way up the agenda, if it indeed was on there in the first place. Whatever anyone thinks of what’s gone before, this is a step forward for the platform. :ride_on:


Good to see zwift improving :clap:t2: Dealt with this quickly and efficiently, and no one lost any face…

Thank you for information update.
Can we assume you have some checks in place when changes are made ‘out of game’ or ‘not active in an event’ that they are generally acceptable changes.
As far as I am aware very few people get shorter through their life until the point when they are probably too old to go any where near a bike.

Yes, indeed.

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Great news Zwift.

Congratulations to all Zwift team who are working on this topic👏
Good improvement into the game !
Unfortunately due to a minority of riders using this kind of practice we are all impacted.
I would like to say thank you @Luciano_Pollastri_ZE for her effort to identify/explained and share on social media this practice.
For my point of view he is also key user for this new update.
Ride on.


I’d like to thank Luciano and the wider Zwift community for driving the fastest and most effective piece of Zwift development in the last 3 years.


Luciano’s Law :wink:




Well done to Zwift on getting on with this.

No doubt there were missteps along the way, but if this results in a focussed effort to support community racing it will really elevate the platform.

Fingers crossed this is a real turning point and the motivation is now there to make this the platform it can be for fair E-Racing.


Your quoting yourself is not an assurance that you’ve understood @Ian_Attoe 's point.

I would think it’s not unreasonable to instigate some fairly simple rules for acceptable height changes.

  • Firstly, make it abundantly clear at the registration stage that alterations are restricted.
  • Only allow subsequent height increases for Zwifters under the age of 25.
  • Allow only height decreases for Zwifters over the age of 35
  • Allow only height decreases of 1cm at a time.
  • If a Zwifter has decreased height in the last, say, 5 years, do not allow any further decrease.

As well as deterring height doping, these rules would disincentivise account-sharing.

Similar rules could be instigated for acceptable weight changes.

  • It could be formulated as [mimimum permissible weight] = [old weight] x e^(-[days elapsed]/350)
    This would only allow weight decreases of, at most, approximately 0.3% per 100kg per 24 hours - if this discourages crash-dieting and weight-obsession, that’s all the better.
  • When entering weight alterations, Zwift could straightforwardly state the permissible minimum.
  • If you haven’t updated your weight for, say, 50 days, Zwift should pop up a dialogue box the next time you enter the game, to prompt you to validate your weight, even if this means just verifying that your weight hasn’t changed.

IMO, this is unacceptable: you shouldn’t be able to declare your weight at 67.5kg one day, then eight days later be racing at 64kg.


Luciano is male.

Except for one problematic thing. Your example highlights an potential issue. You don’t know the rider’s correct weight. As has been mentioned in other threads, weight changes (and height?) are evidently permitted in order to adjust difficulty for a rider who wants to enter a group ride that will be at a pace either too difficult or too easy.

So, a change in weight would have to be analyzed by the system to know what weight was set for which types of events. Opens up other possibilities that riders “oops forgot to change back” – which could be true. Would Zwift want to punitively punish the forgetful?

I think a lot of this goes back to what I’ve mentioned previously. There needs to be a rulebook with more specificity – covering when/how/if whatever metrics can be adjusted and under what circumstances; addressing the issue of sticky watts (is it just a game tactic or a DQ offense), etc etc. This detail should be easily available (maybe a big link on the Zwift Events page) and not buried in some sub sub sub webpage, or require the masses to do forum search to read thru and interpret the 1000s of opinion pieces.

Yes, punish the forgetful.
Zwift needs to place a little separation between free rides , group rides and racing

Maybe a separate race wt entry and race FTP.
I change my ftp all the time for work outs though probably won’t have to since the work out bias has increased.
Also, Zwift ftp didn’t affect Zwift power.
Racers can enter wt to Zwift power.
Make all racers register Zwift Power.

If you find a ride too easy, stick yourself on the MTB, or find a harder ride. Lord knows, there are loads of them. You shouldn’t be f***ing around with your in-game weight to try to fiddle things, and Zwift just needs to make that clear.


I think that it’s often the opposite that is true.

Scenario: New rider, quite unfit and potentially joining Zwift to lose some weight. Majority of group rides too fast for them. It’s common in entry level groups (Herd, ZER, Pack, etc, etc) to suggest they drop their weight in group rides only so that they are able to take part in the ride, enjoy it, get fitter and be part of the community.

I have absolutely no issue with that at all.


There are 10 D-paced social rides between 5pm and 7pm tonight! The calendar is teeming with slow beginners’ rides, which is great. I get that the Herd etc philosophy is to all stay together, which is all very lovely and I’m sure it makes you feel all fuzzy inside, but you’re not being honest with yourself if you have to halve your weight to keep up - where’s the satisfaction in that?