Thanks for doing these tests. Pretty much what I expected but good to confirm. One thing that could be added (though not necessarily relevant to Zwift's shorter races): even with modern nutrition and trained guts, riding hard consumes calories faster than the human body can absorb them. A heavier rider doing more absolute watts to keep up on multiple long climbs will feel the effect sooner than a lighter one.
Good video. Zwift's UI has created a bit of a myth that its only Wkg that matter. It really doesn't if the road is flat. At 0% gradient, gravity is not acting as a resistive force. Only rolling resistance and aerodynamic drag. Watts/CdA is the correct metric to calculate speed at 0%. Your weight might influence your frontal area, depending where you carry it. But, until the road turns up, it is only watts, height, and bike choice that influence speed. Aerodynamic drag increases exponentially with speed. At ~30kph+ aerodynamic drag, even at mild gradients, is your biggest resistive force. This is why indieVelo shows speed not Wkg. Its the same for draft benefit, it increased exponentially with speed because it reduces the drag coefficient. Its for this reason that many outdoor riders shave their legs. Be more Aero 😃 But please keep this quiet, we don't want this information getting out there. Otherwise people might focus on getting faster rather than getting lighter.
Great video. Thank you for sharing it with us. I thought the conclusion about the combined weight of the athlete and the bike was fantastic. It seems like an obvious thing, but almost no one remembers it. Congratulations!
This is why I, a lighter rider, didn't like the w/kg categories. Zwift levels out the playing field uphill whilst I got destroyed on the flat and downhill. I still have this problem today of course. I'll summit a climb with others at the same w/kg and get dropped downhill because there is no cornering etc where a lighter rider would have an advantage.
Something to note about losing weight for performance. I personally found that when I maintained my fitness and excersise level but lost about 10% of my body weight, I had an improved W/kg. But that also came with a small reduction in peak power. If you are already pretty fit, reducing weight can also reduce a small amount of muscle mass too.
Watts matter. I went from 140lbs & like 320W FTP to 165-170lbs @ 360W FTP and zwift races are much easier now. I found from 140-160 my W/KG scales pretty well with my body mass. But above about 160lbs the trend doesn't hold up for me personally. Even with less W/kG in zwift races the gain I got being able to rest in the back of the field paid off. I don't really have issues climbing unless the grade is above 14%. Purely anecdotal, one person. But yea my take away is Raw Watts matter. Zwifters are way to focused on W/KG. And this is all without gym work, I bet I could carry more body mass if I did it with lean muscle. But don't tell anyone in ZRL A1 East, I don't need more competition. Also it's improved my real world cycling performances, watt/kg is really dependent on geography. If you are racing in most of the US, a little extra mass helps.
In Zwift races drafting is a big part and the heavier you are the bigger the watt saving in draft. That is probably one of the reasons. But like you said, that goes only up to a point.
Interesting video but in reality of racing on Zwift it missing the group effect equation VS solo ride that can apply only for TT effort . Draft effects is very important on zwift weight & height combined of alls riders can influence a lot your own performance much more than IRL
@@xavierlecourt9385 Ye I don't contradict that whatsoever. The purpose of these videos was to merely document how does the Zwift behave. (And it is still important in cases when you do not draft - when attacking, when dropped, and even in draft there is the effect to some extent).
@@RoadtoA understood keep training, consistency is key on ZWIFT to gain stamina for pass to top A I believe that some focus on specific effort must be achieved, race IN OUT is fun but slowdown progress , lack of structure. Enjoy always like to see you suffer 😉
Great video. I'm a heavy (92kg) Cat D. Since you did this video using Cat D power, 2.5wkg, I'd be interested to know the difference between real weights in Cat D. 80kg - 100kg.
You can just double the difference in the test. It might not be completely linear due to different impact of gravity/aerodynamics, but the numbers won't be completely off.
Would you be able to perform same test on the Trainingpeaks Virtual? Better physics. George Gilbert should have done a good job in the realm of reality.
George has implemented good physics in TPV. Very similar to Zwift. The main difference is he doesn't expose wkg in the UI. Because he knows WKG isn't relevant in most instances except hill climbing. Aerodynamic drag increases exponentially with speed. Once you are riding at over 30kph, its pretty much the largest force against you, even on a +5% gradient. Watts/CdA is more important in most scenarios. Reduce CdA by drafting or going Aero.
The bike weight being constant is not the only variable. There should also be rolling resistantance and aero drag which would affect the lighter rider more as a porportion to their power output. Say 25 watts rolling and 50 watts aero as an example, it would only leave the lighter rider 100 watts(1.3w/kg) to overcome gravity. It would leave the heavier rider 125 watts(1.44w/kg) to overcome gravity
I thought Zwift used some measure of drag coefficient, based on weight, where the heavier rider has slightly higher drag. In other words, needs greater power to overcome higher drag. Is that not true?
It is, if you look at the previous video (ua-cam.com/video/Q5gHYz8Q54k/v-deo.html) you will see what the effect is. On climbs that is negligible though.
Good video! I would think it would also be independent of the equipment factor not be the same, as the only way I could think of equal W/kg would result in a equal speed is when the riders go straight up a hill vertically. I have one problem with the ending of your video: you have shown throughout the video that it is faulty to assume equal W/kg mean the same speed for riders with differing weights on climbs - the heavier rider would be faster. And then in the example at the end you say that the heavier Pro rider would not be able to hang with the lighter Pro because he could not get to the same W/kg. But haven't you established just before that he does not need to get to the same W/kg because he will have the same speed already at a lower W/kg level? He certainly needs higher raw watts than the lighter rider, but not the same W/kg.
But the heavier you are the harder it will be to maintain similar w/kg as for the lighter rider. Also, it highlights that moving out from the categorization based on w/kg is a good move.
yes excatly. As mid light weight B rider, i sometimes felt racing was pointless that I always get destroyed by eithet heavy 4 wkg edge riders or extremely light japanese riders 4.5 wkg still under 240 ftp. So I agree that zrs makes lot more sense than simple wkg.
How can you explain that a person with an average absolute power of 250 watts and a weight of 60 kg showed a better time than someone with 300 watts and a weight of 75 kg on a slightly hilly course, which would be simply impossible in real life?
Well on Zwift, it's because that person had better w/kg. In real life there are way more factors coming in the equation. How hilly? What's the surface? How heavy equipment? How aero is the eequipment? How good is the equipment? Is it windy? This video wasn't to test if it works like in real life. It was to see how exactly DOES it work.
@RoadtoA Zwift primarily relies on w/kg and then applies a small correction afterward, which leads to such an imbalance. To see this in action, ride a course at 280 watts with a higher weight, then test how much power is required with a lower weight to achieve the same time.
@ understood. That would be interesting! But I can't really imagine how would I execute it - do you have any ideas? I am happy to execute it, but what pace do I set to ensure the same time?
I see your point. I wasn't including the bike weight into this calculation (I should have for the consistency's sake). But the calculation would be different if I did: Pog: 66 kg + 7 kg = 73 kg * 7 wkg = 511 W Aert: 78 kg + 7 kg = 85 kg * 7 wkg = 595 W Don't forget, the argument here was how many more watts does heavier rider need to produce. :)
There is no sprinting test, no continues up and down hills test, the power only set as 175w and 200w.(10kg weight difference). What about 120w and 260w, 50kg weight difference? Test more plz, even though this is not scientific research.
@@Stavros_Polymeropoulos I'll see, at the moment I have several videos planned. I agree it could be interesting but since it's not actionable I'm not sure the video would bring any value (other than entertainment).
Another great video! Sorry if I inspired you to do so much climbing! I actually got my maths wrong when I made my comments I divided 175W by 75 not 70! Oops! Would’ve made my vote for the 80kg even more convinced though. Very surprised by the polll…just goes to show how much this sort of info needs to be to shared.
Being a lighter rider(63kg) this explains why when racing I'm having to do more wkgs to keep up or doing more wkgs sat being someone drafting, which seems a bit unfair.
Well, it's easier to reach a given w/kgs for a lighter rider, so that equals the equation some. Everyone has to use what is given to him by God/Nature and get the best out of him/herself. No point in comparing outside of competitions.
Suppose we have two riders, 100kg and 50kg, both riding at 3w/kg. But let’s say they’re on 9kg bikes. If you add that bike weight to the rider’s weight and calculate the true w/kg, you get this: 100kg rider + 9kg bike @ 300 watts = 2.75w/kg 50kg rider + 9kg bike @150 watts = 2.54w/kg So even though both riders are holding 3w/kg, the heavier rider is holding a higher true w/kg.
This test is not close to what the complaint is about. Your differences are 10 kilos or 20 pounds look at a rider that’s 220 pounds 6’2 vs 70 kilos that’s the difference. Bottom line many lie about weight and sand bag their way on zwift.
@@RoadtoA "Suppose we have two riders, 100kg and 50kg, both riding at 3w/kg. But let’s say they’re on 9kg bikes. If you add that bike weight to the rider’s weight and calculate the true w/kg, you get this:" "100kg rider + 9kg bike @ 300 watts = 2.75w/kg 50kg rider + 9kg bike @150 watts = 2.54w/kg So even though both riders are holding 3w/kg, the heavier rider is holding a higher true w/kg."
@@RoadtoA Yes I know, I came across an article on Zwift Insider I think and thought about this video, just guys in your comments think a heavy rider has an advantage on a hill lol,they maybe didnt watch the full video.
@@egardner1096 I think this way of thinking is based in the former categorization system where in your category basically everyone was doing similar wkg, but the heavy riders were faster. At that point it's hard to realize there's probably more fitness/training behind the heavy rider doing the same wkg. :-)
Thanks for doing these tests. Pretty much what I expected but good to confirm.
One thing that could be added (though not necessarily relevant to Zwift's shorter races): even with modern nutrition and trained guts, riding hard consumes calories faster than the human body can absorb them. A heavier rider doing more absolute watts to keep up on multiple long climbs will feel the effect sooner than a lighter one.
@@eloann That's actually a fantastic point! Pinned.
Many, MANY of you asked for this video. So here it is. Hope you like it and if you do, subscribe for more videos like this!
Good video.
Zwift's UI has created a bit of a myth that its only Wkg that matter. It really doesn't if the road is flat. At 0% gradient, gravity is not acting as a resistive force. Only rolling resistance and aerodynamic drag.
Watts/CdA is the correct metric to calculate speed at 0%. Your weight might influence your frontal area, depending where you carry it. But, until the road turns up, it is only watts, height, and bike choice that influence speed.
Aerodynamic drag increases exponentially with speed. At ~30kph+ aerodynamic drag, even at mild gradients, is your biggest resistive force. This is why indieVelo shows speed not Wkg. Its the same for draft benefit, it increased exponentially with speed because it reduces the drag coefficient.
Its for this reason that many outdoor riders shave their legs. Be more Aero 😃
But please keep this quiet, we don't want this information getting out there. Otherwise people might focus on getting faster rather than getting lighter.
Nice video professor 🙇♂️. Lots of practical points are now included in this video.
@@benjapolcycling professor? 🤣🤣
Great video. Thank you for sharing it with us. I thought the conclusion about the combined weight of the athlete and the bike was fantastic. It seems like an obvious thing, but almost no one remembers it. Congratulations!
@@Andrade-Zwift-Racing 🫡
yay, my comment was featured! Great video. Different results than i expected!
Oh yea!
This is why I, a lighter rider, didn't like the w/kg categories. Zwift levels out the playing field uphill whilst I got destroyed on the flat and downhill.
I still have this problem today of course. I'll summit a climb with others at the same w/kg and get dropped downhill because there is no cornering etc where a lighter rider would have an advantage.
Great video
Thank you 🫡
My respect to you sir for doing your best to get it right!
@@RhettCrowell 🫡
Really nice presentation of the facts- great video 😊
@@crosshaircycling7156 thank you 🫡
Something to note about losing weight for performance. I personally found that when I maintained my fitness and excersise level but lost about 10% of my body weight, I had an improved W/kg. But that also came with a small reduction in peak power. If you are already pretty fit, reducing weight can also reduce a small amount of muscle mass too.
I have the same experience with the lower peak power. Good point.
Watts matter. I went from 140lbs & like 320W FTP to 165-170lbs @ 360W FTP and zwift races are much easier now. I found from 140-160 my W/KG scales pretty well with my body mass. But above about 160lbs the trend doesn't hold up for me personally. Even with less W/kG in zwift races the gain I got being able to rest in the back of the field paid off. I don't really have issues climbing unless the grade is above 14%.
Purely anecdotal, one person. But yea my take away is Raw Watts matter. Zwifters are way to focused on W/KG. And this is all without gym work, I bet I could carry more body mass if I did it with lean muscle.
But don't tell anyone in ZRL A1 East, I don't need more competition.
Also it's improved my real world cycling performances, watt/kg is really dependent on geography. If you are racing in most of the US, a little extra mass helps.
In Zwift races drafting is a big part and the heavier you are the bigger the watt saving in draft. That is probably one of the reasons. But like you said, that goes only up to a point.
Great 2nd video, I think this all highlights why Zwift moved to ZRS instead of the w/kg category system they had before.
@@syctris8742 exactly! This is exactly what I was thinking seeing the results.
Current measures to evaluate a riders power is no longer ftp, ftp/kg, is 5min power raw times 5min w/kg. Because the raw power is really important.
Interesting video but in reality of racing on Zwift it missing the group effect equation VS solo ride that can apply only for TT effort .
Draft effects is very important on zwift weight & height combined of alls riders can influence a lot your own performance much more than IRL
@@xavierlecourt9385 Ye I don't contradict that whatsoever. The purpose of these videos was to merely document how does the Zwift behave. (And it is still important in cases when you do not draft - when attacking, when dropped, and even in draft there is the effect to some extent).
@@RoadtoA understood keep training, consistency is key on ZWIFT to gain stamina for pass to top A I believe that some focus on specific effort must be achieved, race IN OUT is fun but slowdown progress , lack of structure.
Enjoy always like to see you suffer 😉
that was exactly what I answered on the pool, the same bike would give an advantage to the rider with more output power. That is physics!
@@cyclingcomputer you were right!
Great video. I'm a heavy (92kg) Cat D. Since you did this video using Cat D power, 2.5wkg, I'd be interested to know the difference between real weights in Cat D. 80kg - 100kg.
You can just double the difference in the test. It might not be completely linear due to different impact of gravity/aerodynamics, but the numbers won't be completely off.
@RoadtoA Thanks, that's what I thought but wasn't sure.
Would you be able to perform same test on the Trainingpeaks Virtual? Better physics. George Gilbert should have done a good job in the realm of reality.
I have not yet tried Trainingpeaks Virtual. But maybe in the future?
George has implemented good physics in TPV. Very similar to Zwift. The main difference is he doesn't expose wkg in the UI. Because he knows WKG isn't relevant in most instances except hill climbing.
Aerodynamic drag increases exponentially with speed. Once you are riding at over 30kph, its pretty much the largest force against you, even on a +5% gradient. Watts/CdA is more important in most scenarios. Reduce CdA by drafting or going Aero.
So I guess I’ll weight dope the other direction now! 😜
I...uhh....😅
fascinating
@@JayB9127 🫡
The bike weight being constant is not the only variable. There should also be rolling resistantance and aero drag which would affect the lighter rider more as a porportion to their power output.
Say 25 watts rolling and 50 watts aero as an example, it would only leave the lighter rider 100 watts(1.3w/kg) to overcome gravity. It would leave the heavier rider 125 watts(1.44w/kg) to overcome gravity
You are right, that's actually something I was talking about in the first video. That said, when climbing the aero drag is negligible.
I've actually recently learned rolling resistance increases with weight so that bit should even out
@@eloann That's a little out of my comfort zone but doesn't that even out by heavier riders having more tyre pressure?
I thought Zwift used some measure of drag coefficient, based on weight, where the heavier rider has slightly higher drag. In other words, needs greater power to overcome higher drag. Is that not true?
It is, if you look at the previous video (ua-cam.com/video/Q5gHYz8Q54k/v-deo.html) you will see what the effect is. On climbs that is negligible though.
Good video! I would think it would also be independent of the equipment factor not be the same, as the only way I could think of equal W/kg would result in a equal speed is when the riders go straight up a hill vertically. I have one problem with the ending of your video: you have shown throughout the video that it is faulty to assume equal W/kg mean the same speed for riders with differing weights on climbs - the heavier rider would be faster. And then in the example at the end you say that the heavier Pro rider would not be able to hang with the lighter Pro because he could not get to the same W/kg. But haven't you established just before that he does not need to get to the same W/kg because he will have the same speed already at a lower W/kg level? He certainly needs higher raw watts than the lighter rider, but not the same W/kg.
@@css20080301 sure, that was simplification, but the heavier pro rider would still need an insane amount of raw wattage.
Can you test this for a 90kg rider? (Asking for a friend) 😂
Great video.
@@camb210 😐😂
Speed... Speed is everything. Heavier rider goes faster on flat, uphill and downhill
@@rockycycling2102 True! Although intuitivelly I'd expect the heavier rider to be slowed by the gravity way more on the climb.
Don't high carbohydrate eating habits improve performance while losing weight?
I would say this is too complex of a problem for a simple yes/no answer.
As expected. We all know heavier rider always win if same or similar wkg.
But the heavier you are the harder it will be to maintain similar w/kg as for the lighter rider.
Also, it highlights that moving out from the categorization based on w/kg is a good move.
yes excatly. As mid light weight B rider, i sometimes felt racing was pointless that I always get destroyed by eithet heavy 4 wkg edge riders or extremely light japanese riders 4.5 wkg still under 240 ftp. So I agree that zrs makes lot more sense than simple wkg.
How can you explain that a person with an average absolute power of 250 watts and a weight of 60 kg showed a better time than someone with 300 watts and a weight of 75 kg on a slightly hilly course, which would be simply impossible in real life?
Well on Zwift, it's because that person had better w/kg.
In real life there are way more factors coming in the equation. How hilly? What's the surface? How heavy equipment? How aero is the eequipment? How good is the equipment? Is it windy?
This video wasn't to test if it works like in real life. It was to see how exactly DOES it work.
@RoadtoA Zwift primarily relies on w/kg and then applies a small correction afterward, which leads to such an imbalance. To see this in action, ride a course at 280 watts with a higher weight, then test how much power is required with a lower weight to achieve the same time.
@@I-avp-I You mean like this? 🙂
ua-cam.com/video/Q5gHYz8Q54k/v-deo.html
@@RoadtoA No. The main focus should be on achieving the same time to clearly see the difference in absolute watts and w/kg.
@ understood. That would be interesting! But I can't really imagine how would I execute it - do you have any ideas? I am happy to execute it, but what pace do I set to ensure the same time?
Height also matters on zwift, taller riders same w/kg always lose
It does, but that is not something that is actionable (besides cheating but let's not get into that here).
Wrong....?!? 9:35
So... 7 w/kg = same effort. Ok. 462/66+7 (bike)=6.33 and 549/78+7 (bike)=6.42 Pogachar will lose.
Its from ur own math from video.
I see your point. I wasn't including the bike weight into this calculation (I should have for the consistency's sake). But the calculation would be different if I did:
Pog: 66 kg + 7 kg = 73 kg * 7 wkg = 511 W
Aert: 78 kg + 7 kg = 85 kg * 7 wkg = 595 W
Don't forget, the argument here was how many more watts does heavier rider need to produce. :)
There is no sprinting test, no continues up and down hills test, the power only set as 175w and 200w.(10kg weight difference). What about 120w and 260w, 50kg weight difference? Test more plz, even though this is not scientific research.
@@Taylor-Ma you are joking but there are guys who already asked me to do the same test for height and trainer difficulty settings 😂
@@RoadtoA The height setting could be interesting tho, just to see how it affects the CdA
@@Stavros_Polymeropoulos I'll see, at the moment I have several videos planned. I agree it could be interesting but since it's not actionable I'm not sure the video would bring any value (other than entertainment).
Another great video! Sorry if I inspired you to do so much climbing! I actually got my maths wrong when I made my comments I divided 175W by 75 not 70! Oops! Would’ve made my vote for the 80kg even more convinced though. Very surprised by the polll…just goes to show how much this sort of info needs to be to shared.
This also shows why wkg categories are stupid, the heavier guys could win on literally every course in the lower categories
Being a lighter rider(63kg) this explains why when racing I'm having to do more wkgs to keep up or doing more wkgs sat being someone drafting, which seems a bit unfair.
Well, it's easier to reach a given w/kgs for a lighter rider, so that equals the equation some. Everyone has to use what is given to him by God/Nature and get the best out of him/herself. No point in comparing outside of competitions.
Suppose we have two riders, 100kg and 50kg, both riding at 3w/kg. But let’s say they’re on 9kg bikes. If you add that bike weight to the rider’s weight and calculate the true w/kg, you get this:
100kg rider + 9kg bike @ 300 watts = 2.75w/kg
50kg rider + 9kg bike @150 watts = 2.54w/kg
So even though both riders are holding 3w/kg, the heavier rider is holding a higher true w/kg.
@@egardner1096 I did a race yesturday, a guy that beat me and did 3.1wkg, while I had to avg 4wkg. Iol
If you think this (as a 66.5kg rider myself), then you aren't a cyclist.
@@benfinesilver2250 I dont think this, it was a quote from Zwift insider explaining why you can't actually see the true wkg on Zwift
This test is not close to what the complaint is about. Your differences are 10 kilos or 20 pounds look at a rider that’s 220 pounds 6’2 vs 70 kilos that’s the difference. Bottom line many lie about weight and sand bag their way on zwift.
"Curious if losing weight will make you faster on Zwift?" Is the pope a catholic?
I mean...looking at the poll results it doesn't seem as a completely clear cut case. ;)
@@RoadtoA "Suppose we have two riders, 100kg and 50kg, both riding at 3w/kg. But let’s say they’re on 9kg bikes. If you add that bike weight to the rider’s weight and calculate the true w/kg, you get this:"
"100kg rider + 9kg bike @ 300 watts = 2.75w/kg
50kg rider + 9kg bike @150 watts = 2.54w/kg
So even though both riders are holding 3w/kg, the heavier rider is holding a higher true w/kg."
@@egardner1096 that's literally one of the things I was talking about in the video ;)
@@RoadtoA Yes I know, I came across an article on Zwift Insider I think and thought about this video, just guys in your comments think a heavy rider has an advantage on a hill lol,they maybe didnt watch the full video.
@@egardner1096 I think this way of thinking is based in the former categorization system where in your category basically everyone was doing similar wkg, but the heavy riders were faster. At that point it's hard to realize there's probably more fitness/training behind the heavy rider doing the same wkg. :-)