Through one ant+ USB dongle my old PerfPRO Studio can handle three different trainers on the one workout (for multiple riders).
I think it can do more, but the license I have prevents more trainers being connected (would need to buy the more expensive license key).
This is a video game and people who take it super-seriously with posts like these are just simply out of touch. Unless weâre all using the exact same hardware and weigh-in on the exact same scale in a controlled environment youâre not talking apples-to-apples in Zwift. Can we just stop with this fantasy that this is a real world competitive environment? Itâs not.
Race against yourself, not others.
I still canât find the exact source myself.
Drivetrain power loss, or better labelled âestimated power lossâ is ABSOLUTELY built into trainers. Not just Wahoo.
The exact amount of power they âaddâ in percentage is an unknown. It could be 1%, it could be 5%. The manufacture adding the highest âerrorâ correction will have the most popular trainer for racing, going forward. Unless, there is some sort of power verification test manufactures have to pass. Never happening.
Anyway, it may have been from engineer Peak Torque in one of his videos. I ainât watching them all againâŚ
Hereâs him mentioning it in his comments section.
Peak Torque
âWe need to stop thinking that the Kickr is the go-to reference. You ride your bike outdoors (remember what it was like before zwift 
). So use the Assiomas as your reference to both. The Kickr power is an algo based (altho very accurate) number. It also involves a fudge factor to take into account drivetrain friction which is different on each bike, which it canât account for.â
Anyone thinking that all trainers and power meters across the Earth are within a 2% tolerance are living in dreamland.
I have an acquaintance who races on Zwift regularly. She bought a new smart trainer recently and discovered it read 50w lower at FTP than her old smart trainer. 50w, not 5⌠50. So, she sold it and went back to the one that said she was World Tour. True story.
Itâs the wild west folks. Accept it.
Itâs unregulated, yep. There are many anecdotes and egregious examples that can be found, daily, yep. There are therefore going to some people in all our races from whom not all the power is not coming from their legs, yes.
However, I donât accept itâs a) deliberate by manufacturers; b) escalating to win at sales or c) the majority of trainers or meters (I think the majority of maybe 10-20% of a field with bad data is calibration) .
I also find it funny that the closest youâve come to posting a âsourceâ says they are âalthou very accurateâ. I actually agree with him but not with you and yet heâs your source. My Assiomaâs are my reference. They record my comparable training data to my Garmin, same as outside, which is why they are my back up source. Iâd be happy to be forced to use them in a race because they read a little higher than my a Core over short efforts and much the same over long.
Newsflash!
When a trainer is advertised as being, say, having within 2% accuracy, thatâs talking about accuracy to itself, how it was set up in the factory and its calibration. It does not mean that the power figures are guaranteed accurate to another trainer or a scientific ergometer within 2%.
Those trying to ensure that everyoneâs âwattsâ are defined exactly the same are chasing an impossible goal.
Over six months ago, when the Wahoo KICKR V5/2020 was released it contained one not insignificant flaw: Itâd overshoot efforts, sometimes by hundreds of watts, when the flywheel speed was low. Meaning, typically when your speed was low and you accelerated, itâd register a false spike. Itâs something I outlined in both my in-depth review at the time (and video), as well as a caveat in my 2020 trainer recommendations guide.
From DC Rainmaker
Thatâs about the only reference I can see to Wahoo Kickr V5 power issues - but they look to have been resolved.
That would be quite a benefit for sprinting.
knew i should have bought a kickr, dammit!
yeah cause no one ever takes video gaming seriously.
See this point made all the time, itâs just a video game so who cares. You might want to look up how much resource the video game industry spends on trying to prevent online cheating, to try and preserve fairness for the majority of players. Can/do they stop it? Of course not. Itâs not an excuse to do little or nothing.
âRace against yourself, not othersâ is a ridiculous concept to post within this discussion; youâre essentially saying Zwift might as well remove racing from the platform.
you kinda said what I meant but a lot better 
Quickly searched through the individual rankings on zwiftpower and noted down what seems to be (what is mentioned in their profile or what they called the primary powermeter in dual analysis) the powermeter used as primary on zwift for the top 50 ranked overall. Excluded the wahoo kickr v5 used for the worlds.
13 kickr 5
8 kickr
8 direto xr-t
5 kickr core
6 h3
2 hammer
2 flux
1 neo 2t
1 stages sb20 bike
1 kickr bike
1 4iii
2 quarq
Would have though that there would be more Neos?
Wahoo and saris sponsoring would perhaps marginally skew things, but I have a quite strong hypothesis that the kickrs are somehow the preferred trainer for top end racing on zwift (26 of 50).
3 people listing pedal based as primary, this is probably low because of the trainer as primary-rule in the prem races.
You might want to look up how much resource the video game industry spends on trying to prevent online cheating, to try and preserve fairness for the majority of players. Can/do they stop it? Of course not.
Thatâs very true. The difference here is that in Zwift, vast majority of people are not intentionally cheating. Theyâre typing in their weight, which can vary widely based on scale used, theyâre using cadence and power meter data that can vary widely as has been proven ad nauseum. There is no standardization of these sensors and therefore the measurements are all over the place - these are the game inputs. Zwift canât control that, unreasonable to expect them to.
What is in control is for people to be level-headed and exercise some common sense about the results of these races. Races are useful to push oneself harder. Moaning and groaning about other cyclists or what tools they use as sensors is an enormous waste of time.
I donât agree at all. Itâs two things.
One is discussed in another thread, fairness in race rules and categorization. We need a system where success, be it with accurate or highly inaccurate equipment, is promoted, i.e. success results in cat/pen promotion.
Saying it doesnât matter because we canât guarantee 100% equipment accuracy anyway is to me like⌠mixing up income spread with theft or something Defaitism. You may accept income spread (or you may not). But that is not a reason to accept theft because âitâs all money in the end and some will have more and others lessâ. You can still fight for fairness in other areas than equipment and it will be worthwhile.
The second thing is equipment in particular. Just because it is unrealistic to expect 100% comparability and fairness doesnât mean there are no benefits to adding some regulations. Just like regulations in the judicial sphere wonât stop crime, they still make things a little better. Where exactly to draw the line though, where the benefits are outweighed by customer churn or similar, is a decision for Zwift to make. But there can still be a line, you donât have to give it up.
Maybe the kickr is just the default choice, like how some people buy a Toyota.
I do have a neo, neo 2T and a Kickr Bike, they all perform about the same, but the kickr bike does not like my feeble sprint efforts, it smells badly.
Thankfully Iâm not doing 1240w anymore (at 60kg back in those days), or I might have the trainer version of Chernobyl happen.
All three of the trainers I have fairly well reflect the power meters I have on my real bikes, a quarq on the S5 and Dura Ace 9100 power meter on the Canyon.