zPower: Don't be a "Flier"

(D) #341

If you’re talking about the forward direction sprint on Watopia, you might want to recheck some of your calculations, especially the distance as the forward direction sprint is quite a bit longer than 200m.

(malcolm may (WCC) C) #342

I’m not calculating anything. It comes up in stava as a 200 m sprint. The segments seem to vary depending on your lap, or your route. So maybe you haven’t crossed it yet. It sticks out becasue most are in tenths of a mile. 

Ok you found the issue. While its called 200 m final strint. It isn’t. Its more like 300+


Final 200m

Virtual Ride Segment Temotu Province, Solomon Islands

  • 0.2mi
  • 0%
  • 5ft
  • 6ft
  • 1ft


217,085 ATTEMPTS BY 24,510 PEOPLE

(Liam) #343


mal may January 25, 2016 09:56

What has watts per kilo got to do with it? People cheat on their weight and blame zpower. The smart trainer people do the same. W p kg is all about what weight you say you are. It becomes a meaningless contribution to the problem. If I weighed 70 kgs I’d never raise a sweat on the bike. Wkg ppfft. I see them coming past at 4 wpg and when I look at their data they are doing less than 200 watts. 


I find the Zwift weight algorithm pretty damn accurate. I am a light rider. Under 60 kilos. In real life I get KOMs but really struggle on the flats and downhills.

I have done some Zwfit races and have trouble on the flats. If I lose contact with the group, I can’t get back on. But I kill people on the climbs. In Zwift races, I can get dropped on the downhills if not tucked in behind someone, just like in real life.

My point is if you are light or weight doping, you really get screwed on the flats and on the downhills on Zwift just like in real life.Being light is only an advantage on the hills.

I wish all road races were just a hill climb. I am a one trick pony.

(Liam) #344

There are sure a lot of fast females on Zwift now. Gender doping?

(Samuel Mendelow) #345

No, they are getting ready for the Velociio SRAM competition! Lucky girls!!

(Magic 10) #346

I’m only using zwift to train once during the week and sometimes at weekend I cannot go outside (night or raining)

Training with power is something else and once I could not by a power meter I can live with the errors

At the moment I’m waiting for a friend to test my Tacx Satiri (old) with his bike with Stages but before I set up my trainer I went to a site - Power Curve - and get a trainer that have a similar power curve

I hope that the diference between the picture and the test with the Stages to be short but I can live with that
I don’t intendo to race virtually or get the jerseys so I will keep training to be a beter cyclist when I have the opportunity to go to the road ´

When I get the test done I will give you feedback



(Peter Harris PACK) #347

Okay … sorry … I’m not going to read all 340+ comments! But a comment posted maybe a year ago (and possibly repeated since then) suggested having different “classes” of riders: those using PMs and those using zPower. That might be a good idea and I’ll elaborate. I think there are a few types of riders on Zwift - the dead-serious competitive all-in cyclist, the avid cyclist, and the casual cyclist. That’s three … maybe there are only two classes in the eyes of some or maybe there are more than three but this is my quickie view of the Zwift world. I would expect the dead-serious cyclist to use a power meter and/or a smart trainer and would closely track their speed, watts, FTP, etc. often in a focused training regimen. The casual cyclist would have a lower-end classic trainer and the minimum sensors to make Zwift work for them and wouldn’t pay much attention to speed, watts, etc… Bike computer? Probably not. The avid cyclist would fall somewhere in-between - probably a nice classic trainer or a low-end smart trainer and would watch their metrics but without a defined training plan or end goal. They most likely have a good bike computer.

For the dead-serious cyclist, Zwift is their cycling lab. It gives them the data they need to improve their cycling, possibly for competition but maybe only because they want to be the very best they can be at what they love. I would make a wild a$$ guess that the dead-serious cyclist uses Zwift year-around. The avid cyclist (I put myself in this category) wants to improve, if possible, but doesn’t necessarily use Zwift for that. They maybe most interested in staying in good riding condition and using Zwift off-season when it’s cold and windy and the roads are covered with snow and ice, or during the on-season if there are a string of rainy days and they’re just itching to be on the bike. They’re interested in their metrics but their metrics aren’t the driving force behind their use of Zwift. They want to stay fit so that when spring rolls around they won’t have to start from where they left off last fall. The casual cyclist would use Zwift to ride around the Watopia neighborhood because they can’t get out for whatever reason - darkness, weather, work schedule - but are interested in trying to lose a few pounds or just generally staying in shape.

IMO, the paragraphs above possibly argue for two categories of rider in Zwift, as the previous poster suggested - the PM category and the zPower category. Since there appear to possibly be divergences in data from PMs and zPower, why not segregate the two groups? I wouldn’t necessarily have separate virtual worlds for them but separate leaderboards, jerseys, etc. As a zPower user, I wouldn’t be able to compare myself to the PM users (nor would it make sense for me to do so) and wouldn’t earn a position on their leaderboards, wouldn’t rack up their achievements, and I’m okay with that. The dead-serious cyclists are using Zwift for a different reason than the avid and casual cyclists and should maybe be treated differently.

As an avid cyclist at age 60+, I’m sometimes just trying to hang on to what I have and if I improve a little along the way then that’s good but a PM is not likely in my future. I’m not in it for what the dead-serious cyclists are (and I admire them for their dedication and focus, btw).

My two cents. Feel free to agree/disagree!

(Chris B (D)) #348

There are two groups, those that want to/can afford to spend $1000 on a power meter/smart trainer set, and those that can’t.

Z-power, when set up right, should actually be as accurate as any of the non-force gauge (so not strain gauge or ceramic force gauge) systems. All they use, is a known curve. If the trainer spins at 60km/hr, that’s 300W sort of thing. So if you have a z-power trainer and set it up correctly, you will not be a “flier”. You might be +/-5%, buy unless you’re already in the top 10 riders on Zwift, this won’t make you a flier. 

Get out there and enjoy it. 

(Craig Howard KISS B) #349

Eurgh.strain guage trolling again… Where does it end?

Strain gauges are calibrated and PM tech also incorporates temp and other adjustment factors to give reliable and consistent absolute data. You’re telling me a fluid, gel or mag turbo is as accurate? Get off it matey!

I’ve already compared my pm data to that of my properly setup Elite fluid turbo and the further you strayed from 200w the worse it was. By about 400w the turbo was nearly 80w out. That isn’t consistent, it isn’t +/-5%, it’s around 20% out so please don’t spout such rubbish because other readers may believe it. Remember this is also just my turbo setup which I will put money on to be completely different to that of the exact same turbo if I bought it again. Different manufacturers will also be wildly out and differing to each other - you’ll understand that being an engineer right?

Base my recorded and evaluated 20% power offset onto a device such as a dumb trainer with no temperature offset or other metric stability and you really are a long way off any kind of real, reliable and more importantly,  absolute reference point for training. but it’s fine. Zwift is all about fun but the fun ends when it’s a mix of zpower and real power.

I also believe serious power meter training cyclists are not just jumping on Zwift to get race fit. You wouldn’t do that in the real world either.  I use it as a stimulant while I run through my preconceived training session targeting the watts and intervals I need to hit in order to gain the tss required for that days training. 

If online racing was properly introduced,  then Zwift to me, would be much more interesting.  

(Chris B (D)) #350

@Craig. How did you know I’m an engineer? I didn’t think I disclosed that. 


You are right, if someone raises the room temperature whilst riding in Zwift, or rides for such a short time that they don’t reach equilibrium, then there will be a shift if resistance at a given speed, which translates to a change to their output power. I’m making the assumption that people who are winning the KoM’s are riding more than ten minutes and don’t have a room that goes from 40F to 80F during their workout. The non-strain gauge/ceramic trainers, unless they have a temperature senaor, also suffer from this. 

As for your systems 20% inaccuracy, I cannot comment. Experimental set up is  complex and takes a lot of care. My setup uses a very large heat sink, ie the atmosphere, and reaches steady state within five minutes. The power calculation is really really simple then  

So I maintain, a z-power set up is every bit as accurate as a non-strain gauge/ceramic setup, with the addition of my two assumptions about ride time and room temperature  

the reason temperature is more important on real world power meters, is because outside you can start a ride I  32F conditions and finish in 80F. But most people don’t suffer from those extremes inside 

People are overly scared of power calculations, even though the basis for power calculations was taught in high school physics. Strain gauges are nothing too fancy, just very long resistors which are normally glues onto the thing you’re trying to measure the stain in.


(Peter Harris PACK) #351

Steve, I’ll take a slight exception to your statement that “those that want to/can afford to spend $1000 on a power meter/smart trainer set, and those that can’t.” It’s not always those who can’t afford it - in my case I CAN, I just elect not to do so. This is a too-generic statement but I’ll make it anyway: at my age and with my particular level of enthusiasm for cycling, spending the money just doesn’t make sense. For ME. I am 150% thumbs-up to those who want to and can. On Zwift, I’m only comparing myself to myself and if I can maintain my metrics - flawed or not - then I’m happy as long as Zwift is measuring them consistently. If I see a little improvement then that’s a plus.

Craig - I assume you’re a serious all-in cyclist since you’re using some terminology I can’t even relate to! But it appears you absolutely know what you’re talking about and you make valid points. For me anyway, mixing real power and zPower doesn’t take the fun out of it but maybe that’s because I’m not a serious cyclist - I suppose maybe you meant that it takes the fun out of it for you serious cyclists, and maybe that’s why there should be separate “PM” and “zPower” categories.

BTW, I’m constantly amazed at seeing you guys blow by me when the best I can do is maintain maybe 20-21 mph on the Zwift flats without my legs blowing up! I am just a little envious! :^)

(Chris B (D)) #352

@Peter:  “those that want to/can afford to spend $1000 on a power meter/smart trainer set, and those that can’t.” We’re saying the same thing, some people can afford a power meter, but don’t want one. I see it as:

  1. want a power meter and can afford

  2. either don’t want or can’t afford a power meter  

I too can afford a power meter, but my setup is very consistent, and gives me very repeatable measurements. It has taken some work to get it here, but now I am, it is great. I would like to calibrate it against some power meters and tweak my power curve for my exact setup, but with that done, it is as accurate as any setup (provided I control the variables, such as room temperature, steady state temperature, tires and pressure etc). The only worthwhile addition I want is the active resistance and freewheeling ability of the Tacc Neo etc. 



(Marcus Durant @VanelliCycling) #353

Some info to throw into the mix, I have recently bought a KICKR. I already had a power meter, although the KICKR reportedly being one of the only ones that actually have a strain gauge was part of my purchasing decision as I don’t have a pm on my xc and cx bikes.


  • The power out of the box was -20w av down on my PM @200w 
  • I could get it pretty close by adjusting the belt tension slightly.
  • I would advocate then that this could be anything for any other unit out of the box) - premis, if my unit was ‘in spec’ then could (if my pm is correct) be around ±10%
  • Although over the period of the ride (1-2.5hours), it seems to drift significantly (tbc, still experimenting - prob due to significant heat build up in the resistance unit?)
  • Even on spindown (free wheeling) the KICKR reports power, I assume because its strain gauge is mounted on the resistance unit and not crank-side. This would be a slight advantage in Zwift.
  • I now have my PM controlling the kickr. Best of both worlds for my training needs.


(Hiltja) #354

I know the answer for this problem with the flyers. Zwift should create a VIP-Island for the leaders on the leaderboard. After you (the flyer) get the first place and the leaderjersey, you are transfered to the VIP-Island with all the other “leaders”. There is flying allowed. The flyers can fly and fly and… .The fair and civilized riders stay on watopia to have fun together without the VIP-Riders. That’s a pretty easy way to get rid of the cheaters and Zwift won’t lose riders (and money). The cheaters could be proud because they are VIP’s.



(Marcus Bierlein) #355

I dont’t care about them very much. By the first pass of the KOMs and Sprint I take a look at the leaderboards and decide wether it’s worth going for it or not. But: I really, really hope Zwift is taking care, that not everybody flies up the new mountain route to get the tronbike within a few days. They should take the time a pro needs for the stage and strictly delete all times and elevation gains of people who finish beyond that time.

(malcolm may (WCC) C) #356

I thinnk the leaderboards are fluid. The leaderboard only applies to the current riders on the track. The strava leaderboards are separate, and what you see after you log off. Hence why I never find the little sprints, they are created by strava users, not zwift. Correct me if I am wrong.

(John Clarke Z69+) #357

As regards"Z" power, what does it matter wether anyone is putting in X number of watts / kilo. It’s all about getting on your trainer and having a good workout, and having fun in the process.Some people just get hung up on KOM’s and jerseys. It’s all a bit of fun, so lighten up all those who take it too seriously. It’s just a training tool to get you fit for riding in the real world.

(Matt) #358

Hasn’t anyone ever raced on Tour de Giro? It’s strictly a race oriented format.   It’s been around for years. Same issues there. Unless someone comes out with a $199 smart trainer, this issue isn’t going away.

People just need to get over it and realize IT’S JUST A GAME!!

(Chris Leather) #359

Haven’t read the entirety of this thread so this might have been suggested already, but these people should be flaggied on Strava.

Whether they are genuinely clueless, or really think anyone is going to buy their 800w FTP effort, someone should let them know it isn’t acceptable.

Check out the comments here:


This is what we are up against…

(Matt) #360

Of  course it’s annoying,  but there will always be 5% of people who don’t care. As far as as I know , the issue is with people who have low end, speed-only trainers. They either don’t have the money or the desire to speed a lot of money on trainers… I don’t  think they consider this as cheating.  They just don’t care that much about it because its a casual thing for them.

I have a Tacx Neo /PM setup…this is over $3k in gear not including bike , TV, computer,  internet,subscription, mobile. That’s a small universe of people who can buy into this game. 

I love cycling, but zwift isn’t cycling…it’s it’s own thing.