Sticky watts and activity suppression

Hi all :slight_smile:

Just had issue yesterday on a race, always doing a multiple recording when i ride (i love accurate nbrs)
I ride with a KickR but my power source is an SRM, i always record SRM in double, Zwift + edge 1000, and i also record the KicR power on another edge 1000
Was tired yesterday, but decided to race on TDZ (6), race was hard, and not as usual… arrived at finish line, i saw a different result of watts average between zwift and my garmins, really unusual…
After a bit of research, i find topic about “sticky watt”, and understood… A lot of high powered relaunch on volcano descent(we were 4 on lead, and it soundz good and fun to alternate relaunch and superstuck)
The watt difference was not huge (234 against 245) but enough to bowser me, it also made me pass from CAT B to CAT A racer…

I pass about details, but have two (or 3 :face_with_monocle: ) questions;

I wrote to ZP to delete the race, did someone experiment this? do we have another option to delete a file?

Do somebody know if zwift development team work on something about this problem? It’s hard to get accurate sensors, it’s a shame to have “stupid” issue like this.

“Have to” race on WTRL on Tuesday, with my cool B team, but i guess A cat qualif will be a problem, also if it’s a 5w problem? if someone had the case…?

Thanks a lot, have a nice Sunday

Long life to free wheel :metal:

That wasn’t a very sensible idea, deliberately exploiting sticky watts.

Hi Steve

Definitely not my idea… and not my question… if that’s what you mean,

but thanks for answer…

Email with a link to your Zwiftpower profile. Tell them what happened, that you’ve learned your lesson and will never do it again, and ask if they can annul that race record.


That’s what i did this night when i find the problem source…
Without the “I’ve learned the lesson” :innocent: (although I learned it)

I would appreciate you consider that was not volunteer, really too proud for this kind of move, but i imagine you deal and discuss of a lot of +/- volunteer cheating move on this forum.
But, my case would not be uninteresting on that precise point… always work with SRM, indoor, outdoor, bike is my work, got many bikes with many sensors, and i love numbers and accuracy…
Just had new trainer a few time ago (KickR), and, at the opposite of the old wheel-on i had before, possibility to stop pedaling on descent is possible (impossible because of a recurrent bug on the old one, already with SRM, no more resistance if roll stop turning)
Never heard about Sticky Watt till yesterday and my research…
So, i totally assume the yesterday error, let say than, like french law, you are supposed to know it all :sweat_smile: but, maybe, you should consider than users who don’t have knowledge about that precise can be surprised the first time it happens and, if they are honest can be deserved by the situation

Thanks again for answer, and excuse my broken stupid french English speaking


Well, it’s only 1 race.
If you were truly a B rider, 1 above thresh hold activity won’t put you over.
You must be borderline anyways so you are probably in the correct category.
If that is not the case, your category assignment will be corrected in a few months.
You can still race and you will be with the same people but now you have a red dot instead of a green dot.
I understand that this will affect your team but then I imagine you are a “ringer” for your team.
Your super strong and really help pull your team up but now you are cat A.

To be honest, to have a situation where you are moved to a different cat because of sticky watts is very unusual and , it is my opinion, it never happens accidentally.
It is not an easy situation to replicate.
I’m surprised someone would come on this forum and ask to be excused from benefiting from sticky watts then want to be put into a lower cat.

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Hi Tim :blush:

Ok, get it, i did not exprim well my “feeling(s)” sorry, my english is a bit poor…
Yes, level is level, moving to A cat is not the problem, i’m border line for some monthes, only thing which keep me in b is my low weight and the “250w” rule

Always happy to progress, and really happy to race with A cat if my level admit it !!
Indeed, that’s a problem for this ZRL session, don’t like idea to let my team down…
No, the major problem is my surprise on this, like i said, we dispense a lot of energy and money to find a reliable system, accurate, that’s perfect for training and motivation, specially on winter time, so bad all that can be wasted by an algorithm…
To be clear, i’m not programmer, and i can conceive than, if this problem remain, it’s maybe because it’s hard to solve… I have all the “due respect” to programmers of this nice software/social media
I was not close to suicide when writing my post, just wanted to know if persons experimented this situation, and if ZP is ok with the fact to erase a race than you personally don’t appreciate because of falses values (once again, not a big deal, 10w off, but i have the "impostor syndrome since yesterday :man_facepalming::yum: …)
I love to understand, and more, to control this kind of things, virtual bike is really more complicate than IRL :sweat_smile: exiting, but also sucks sometimes with this kind of surprising issue(s)
I always try to keep disadvantageous system (a little bit) on weight, and sensors, always a bit “extremist” on my way of doing things, and not shouting it everywhere, just like things like this for me (i guess a lot are doing like this)
Sorry for misunderstanding on my post, i really not looking for a kind of twisted forgiveness, just the pleasure to understand…

I don’t understand why sticky watts can’t simply be eliminated, at least for race events.

If the problem is interpreting event-based power reporting correctly at low cadences, just make the stickiness based on cadence for the last >10 seconds (60 rpm and above = 0 or 1 seconds of stickiness, 59 rpm and below add 1 second, maybe an extra second for very low cadences). That way grinding up a hill still gets interpreted correctly but the mash-stop-repeat technique doesn’t work.

If the problem are dropouts, can I tell you about Wahoo Direct Connect technology?

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Sticky watts can be eliminated through rider education - maintaining a pedal stroke after kicking hard, even if it’s just 20 watts.
There are some high-profile riders that are still unaware it provides them free watts and use it regularly.

This happens to mostly power meters, that’s why Zwift only allows trainers as primary power source in top races and they advise if you race to use the trainer.

I don’t think this is something a rider should have to know or care about. And even if they do, they might forget in the heat of the race. (I ride a road single-speed quite a bit so the mash+coast technique is just part of how I’m programmed, then again I always have the trainer as primary so not my problem.)


Zwift can’t eliminate it because it’s happening within the power meters themselves. There’s no indication that the power has gone to zero. As long as you ride semi-realistically for a road cyclist, it won’t come up.

Hi Gerrie
I rode on an other topic that the problem happens also with trainers… did not test…

@Anna_Ronkainen Hi Anna :slight_smile: … i also have this point of view, for me, it happened when i start pedaling “like in IRL”, relaunching hard and going to aero position on a descent, we had a big group just behind us, and were 4 in front, so, the frequency of “relaunch” was high, i guess it was same for the 3 others, not thinking about “sticky watts issue” at this time !! or maybe like me, they did not know about that.
The point of all the system, i guess, is to approach a realistic ride !! not on graphism, for Zwift at least, but on riding experience… we now can have a 5° liberty, a stable bike on which you can sprint at 12w/kg without falling risk, air, tilt…but can’t relaunch hard …
Ok, when you know it, it’s not really hard to think about that, but it still looks like a bug.
So, ok, like James say, it can be resume at rider’s education, but, I hope that we will all agree on the fact that the most logical thing would still be to correct the matrix

Hi Craig :blush:

Not sure of this, The Garmin Edge do not have this issue… when power go to zero, it go to zero, point…or i missed something…

It’s not every powermeter. The problem is that some don’t send updated data when you stop pedaling. If there’s no message until you start pedaling, Zwift has to wait a couple intervals to see if data comes, and then sets the power to zero.

ok, but garmin seem to manage this properly with my SRM, and also with other captor i use (Garmin/Stage/FSA), i’d like to understand why this difference…
But to go in your direction, i also than, on IRL rides, Garmin do not interpret power datas as Strava do, at less on pondered power data… so, i guess it’s a difficult question

If your cadence is >60 rpm, there will be an event at least once per second. Hence, no need to wait for any longer, unless the cadence is lower (or at least getting there).

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Just to give last infos on my personals experience, maybe it will help somebody else, later…
A nice technician from ZP sent me mail, on a friendly and pro way, to inform me they put this race on “ERROR”, so, just ok for me !!
i sent request only two days ago… they were reactive, comprehensive, and I allow myself to consider that they made the right choice with me
I guess answer can be different if you have a “not really serious” account… (i guess…) with lot of DSQ or else… don’t know…
Thx to those who kindly replied, see you IRL, or more probably on Zwift… :metal: