Why Trainer Difficulty IS NOT Virtual Gearing - Zwift
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- เผยแพร่เมื่อ 7 ม.ค. 2021
- This is a follow-up video to a Trainer difficulty video I published about a year ago. I mentioned that a lot of folks call trainer difficulty virtual gearing but didn't really deep dive into WHY it isn't virtual gearing. This video talks more specifically about the algorithm and why it makes the analogy to virtual gearing inaccurate and could send people down the wrong path.
********I am going to state it here in black and white for those who will be quick to challenge this video based on repeated talking points, repeated from my last video: TRAINER DIFFICULTY DOES NOT IMPACT SPEED IN THE GAME. So before you try to straw man my position, that is not what I have presented here. ********
Check out the original video: • ZWIFT- How Trainer Dif...
Check out this research paper outlining the effects of crank inertial load for the actual science behind the phenomenon I discuss in this video: citeseerx.ist.psu.edu/viewdoc/...
If you have any comments or questions, as always, leave them below.
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I'm very skeptical with the momentum portion of your discussion. If I'm on a 15% grade with a low trainer difficulty - of course my flywheel will have a much higher speed vs on a higher tainer dif.... But when I stop pedaling [ go to 0 watts ] I quickly roll to a stop based on my mass [bike included] and the speed i was traveling [slow on a steep climb] the flywheel continues to spin for long after the point in which I have stopped pedaling. Wattage input controls speed. Speed controls momentum. Flywheel is not part of any of these relationships.
You are disregarding the idea of Kinetic Energy. In this case, the energy contained in you and your flywheel when it's already in motion. The measurement units for energy (either potential or released) are joules.
So if an 80kg rides at 20km/h, their kinetic energy will be roughly 1,230 joules (Ek = ½ x 80kg x 5.55m/s2, where 5.5m/s is the same as 20km/h). If the rider is doing 50km/h, their kinetic energy will be nearly seven times higher - 7,720 joules - because the kinetic energy is 1/2 mass times velocity squared.
If you’re traveling 50km/hr on a flat road and you stop pedaling, you’re still moving quickly and won’t slow down very much. You’ve got all this energy which helps to overcome the drag and rolling resistance. So you’ve got a lot of kinetic energy in the system, but the forces that are retarding you are relatively minor, so you don’t slow down very quickly. This applies identically to the flywheel as physics is not going to be altered.
Now, when you’re climbing, you are moving at a slower pace so you have less kinetic energy. When you stop pedaling on a climb you slow down very quickly. This is because you’ve got less energy in the system, plus the resistive force of gravity is significant. If the total resistive power is 400w it would take 19.3seconds (7720/400) to slow down to a stop from 50km/h on the flat as compared to 3 seconds (1230/400) on the climb. What does this mean? Well, the way you pedal in a time trial is different to the way you pedal when you’re climbing. It might not seem obvious when you’re pedaling, but it’s all about motor pattern recruitment.
When you’re time trialing, once you’re up to speed you’ve got a lot of energy in the system and as the pedals go around they’re merely topping up the energy required to sustain a fast pace. In a TT (high speed, flat road, high kinetic energy), the duration that your muscles have to fire is very small. You’re basically firing the muscle for a very short period of time every pedal stroke, but very quickly. When you’re pedaling up a climb (low kinetic energy, traveling slowly, gravity holding you back), your legs impart force on the pedals for a much longer duration throughout the stroke, even though your cadence might the same as when TT’ing.
In short, your motor patterns are significantly different between time trialing and climbing and the resistance simulated by Trainer Difficulty will not negate this fundamental tenet of physics.
To be clear, in the first video as well as in the description I made it abundantly clear that world speed is unaffected, this is a physiological discussion only.
@@EverythingIsPhotogenic Thank you for taking the time to reply. Firstly I must say I may not of explained myself very well in my comment. I understand the physics. ... I think you have enforced my understanding of the algorithm's effect. I would think that the programers do not allow for angular momentum of a flywheel to contribute to my forward progress. I feel they only consider the angular momentum of the in game wheel choice for this contribution. MOST IMPORTANTLY I feel the algorithm computes your wattage input VS the ACTUAL in game % grade and NOT the % grade that the trainer produces. So when you reduce the T.D. to 50% on a 10% it "feels" like a 5% [using the same gear selection]. That is it. Your speed DROPS because you are on still on a 10% grade. Momentum is important - but the algorithm IMHO does not alter what you would experience in real life. At 50% T.D. on the Alpe in the 39x23 you will slow down vs 100% T.D. in the 39x23..... again I'm speculating on the algorithms structure. Have you seen it? I have not.
@@cliffclermont I think my first video would put this more in context. I talk about the algorithmic speed calculation. Effectively there are two concurrent calculations 1. Speed = Watts/kg by grade with a computation for CdA weighting for raw watts on the flats and w/kg on the climbs - this is the only thing that affects your avatar trainer difficulty is ignored. 2. Resistance = world grade * TD%. This one is invisible, this only affects the trainer and how it feels.
The original reason that Trainer difficulty was implemented, and the reason it remains at a 50% default was actually a throwback to the ubiquity of wheel-on trainers before direct drive. Most of those trainers had a max grade of between 6 and 10%. So if you maxed out difficulty and climbed the Alpe, at a certain point, the trainer couldn't add any more resistance, so a person would see gradient go up but it didn't match what they felt. As more direct drive trainers became accessible and affordable, the slider continued to have utility as the bulk of Zwift's riders are amateur and many of them are not committed cyclists. They are recreationally fit and do this for a good workout. Those folks are not capable of the output it really requires to climb epic KOM or the Alpe, but that slider makes it possible. Take for example a 100kg rider, maybe he is brand new to riding and has an FTP of 150 watts. He takes his bike and wants to do the Alpe no matter how long it takes him... 3 hours? Fine. He hits the Alpe and can pedal at a lower difficulty at 120 watts for hours and the game will put him at that speed floor of 2-3mph and make it to the top eventually feeling proud of his effort. If he put his TD at 100%, no dice. He won't get one pedal stroke. Nor would he on the real road. There is a minimum effective power it takes to overcome the gravity and inertia of a climb, even if you have the most aggressive gearing. Trainer difficulty allows you to bypass that lower limit because it's a multivariate calculation that involves independent tasks. It is very difficult to communicate this in a way that everyone accepts unfortunately. But if you really suss it apart, it makes sense. I have had the fortunate opportunity to have been on the platform from very early days. Back then the community was tiny, hundreds, and we had a solid pipeline directly to the developers through community groups. While I have not specifically seen the proprietary code, I have confirmed my understanding of this slider with them, so I am confident in my content, I wouldn't put this up if I wasn't, that would be disingenuous and lead people I care about in this community down the wrong path. Zwift themselves are flummoxed as to how to broadcast this idea to a "pedestrian" audience. They default to the 3 sentence version because that is sufficient for 75% plus of the riders, the remainder of us toil in the wind because Zwift doesn't just come out with an end all, be all TLDR version. I hope this made sense, I totally understood where you were coming from and wanted to put more context behind it.
@@EverythingIsPhotogenic I mostly agree that "world speed is unaffected", except there are boundary conditions to consider. As per my comment yesterday, if you are accelerating uphill at a low TD setting toward the finish line or a sprint, you're adding more KE into the smart trainer's (higher velocity) internal simulation than at 100% TD. Sure, that additional KE gets returned to you, but that's of little consolation to you after the finish line where the clock got stopped, or after the sprint point.
@@chuckb4375 This is a function of how the algorithm handles the descents and to a lesser degree, flats, it isn't as linear. This is why racers prefer a lower TD, because the higher inertia feel really lines up better on the flats. I don't disagree with what you are saying at all. That is really complicated to try to explain to people and I intentionally limited the conversation to the most probative part of the slider and that surrounds climbs. I actually did a tips for racing video recommending that people turn it down for just that reason. It's really a balance. You use the slider to get the needed benefit. I talk about that piece a lot in the first video. These conversations can get really long. Look at this thread, can you imagine trying to cover all of this in a video and keeping the general audience along for the ride? You have to really cover this in bits and pieces so people can take what they need and leave the rest.
Great to see your subscriber numbers growing. You consistently post great quality stuff👍🏻! Keep up. Sending best wishes from NZ
Love your delivery- extremely entertaining- thank you
Thank you for making this video. I'm new to Zwift and I was very confused about trainer difficulty. I got a much better understanding of it now. I like your glasses.
Thanks, that was a well thought out explanation. Learning a lot!
Thanks so much the clear, logical, explanations. Glad I came across your channel.
Interesting explanation - how do you explain the speed reduction on climbs where cadence is maintained in the same gear by increasing power - which on the road equal a maintained speed but in Zwift you are slowed?
awesome video ! on a side note, I find the background music really really distracting !!! . Any reason to include a background music in your videos ?
A minha dúvida é quando paramos de pedalar, o tempo de inércia até a parada total no Zwift é muito menor do que numa Bike de verdade que fica bem mais tempo em movimento até a parada total... Tem como regular isso? Onde? Parabéns pelo canal! 👍👍
Great video and appreciate the way you explain things, I am pretty new to Zwift and have been using about 75% difficulty. Watched this last night but today was thinking, if this is a gradient realism algorithm only - how does it give you a different feel on flats by providing more uncorked momentum on the 100% setting? It should have zero effect on flats, maybe on declines but not flats. I am not disputing you and believe you are correct but I still have a semi hard time with all the talk of everyone saying oh well you still put out the same power regardless of the setting, it just cannot be. I don't have a problem flattening the hills in the game, but would love to have some of the other payoff you say comes with the 100% setting on flats or declines. I want it to feel as real as possible, and I am not interested in tackling the high climbs anyway as I live in the midwest where it is flat. I mostly want a good sim that feels as real as possible, so give me that final assurance somehow that going to 100% will give me that "coasting more" simulation at speed. Keep up the great work!
This was really helpful, thanks so much 🤘
Super helpful explanation of these ideas
. I've been going crazy figuring out why my wahoo has a mind of it's own.
The research paper was very interesting having been published in 2001. Of particular interest to me is the way they used a motorized treadmill with a weight tied to the bike to vary the workload on the flats. I also wonder how the motor driving the treadmill belt was adjusted in the uphill scenario. And the rider had to steer as well? How many broken bones or bikes resulted from this shenanigan? I wonder what the accuracy of power meters was way back then?
I'm not going to delve into the morass of the virtual gearing argument, but for my purposes, as long as I have the physical gearing on my bike to maintain my desired workload in watts at the varied cadences I need to train at and still make it up the virtual hills in Zwift, I'll set the slider as far to the right as possible. If that's not at 100% so be it. I'll still train hard and make gains so should I ever be so lucky to try the real Alpe d'Huez, I might be ready...
Awesome video! I never changed it, so it's at 50%. In real life i've found myself many times on high alpine climbs literally coming to a stop, which is something I never experienced in Zwift's Alpe or Ventoux. Definitely going to move that to 100% in the future.
Exactly! Cyclists who are trying to 'ride indoors' should use 100% - it's a shame the default is 50%, lots of people are going to be surprised come spring. Luckily Zwift is so big that winning anything is (for me) unlikely to say the least.
Best explanation I've seen of this matter, exactly the way I've always thought about it. Kudos to you!
@@okreidieh so what you're saying is that it's not gearing 🤦🏼♀️ good God....
really great explanation. Thank you. Could you do a video on ERG mode as well?
I think I'm going to do a workout video soon including ERG, what are you looking to learn?
@@EverythingIsPhotogenic I’m not sure how it works. Should I be changing gears in erg mode. Is there a specific gear I should be in. Does trainer difficulty affect it. Is there anything in my set up that should be changed ? How should I approach a work out using erg mode or should I turn it off to more/less out of a work out? You know the usual banter of questions :). Really enjoy you videos. I’ve found them very helpful
Hi there ,
Speaking to DS from a few countries for the E sport champs the function wasn’t turned off. It was set to a minimum of 50% as the lowest you could select up to 100% apparently.
I mentioned in the video that it was locked out not turned off
Great explanation and like you said, it's a one-and-zero thing, once you understand what the software does, there is nothing to discuss. And thank you a lot for the insight on the inertia effect! I don't have a power meter on my bike, so I started recently to learn to "feel" a certain wattage on the smart trainer... and I noticed exactly this effect: much easier to hold a power when I'm on the big chainring (and harder gear) than on the smaller one. Since I have a wheel-on trainer, and my wheels are not super light weight (just the stock Giant PA2 that came on my Propel), I think this effect is even more pronounced! Speeding up is harder, but once the wheel is spinning, the inertia is perceivable.
I definitely understand the effects of a lower Trainer Difficulty, and I know how a lower settings make for a poor simulation of the effort of a climb (Alp de Zwift felt downright "easy" compared to a 640m climb near here, with an 5,3% average gradient (ok, it has some 9-10% on the first half and ends with a punchy 10-14% www.strava.com/segments/21197047).
That said, my slider will stay at 50% for the time being for a simple reason: I got a simple wheel-on trainer (Tacx Flow) that can just simulate gradients up to 6%. If I put Trainer Dificulty at 100%, it just means that most climbs will feel the same after just 6%. Keeping the slider at 50% makes it interactive over to a 12% gradient, which makes for a more "realistic" feel, even if it is "easier" that the real gradient. It might make sense to increase it when I ride some flatter/rolling routes, but a 50% difficulty increases the "range" of my trainer. As I'm not a racer and I ride for the joy of it (and just a bit to get better, but not super dedicated to it), that is a compromise I'm of with.
Great video!
I use a Saris M2 which has a TINY flywheel compared to any modern direct drive unit and hadn't really thought much about it in relation to affect that distinction may have on trainer difficulty. I only have the difficulty set to 100% on flat courses or occasionally very long descents as I've been caught out more than a few times unexpectedly slamming into a wall and having to grind gears violently to keep moving. It can be difficult knowing what gear you'll need to be in 50-100 yards away in zwift as opposed to "Outdoors" where the amazingly better graphics makes knowing when to shift so very much easier!
I adjust TD depending on what I'm doing;~100% on flatter courses to stave off boredom, ~50% on rolling or hilly stuff, 20-30% if i'm watching a game with the primary motivation being how OFTEN I want to be shifting.
can you explain the drafting algorithm? I've heard it said in group rides to stay in the "blob" because its easiest, I'm wondering why this is.
So on the real road, drafting cuts your effort by a substantial amount because riders in front of you are cutting the wind in front of you, almost like riding in a vacuum. You can often coast when going upwards of 25-30 MPH. In Zwift they dumbed that down so people can keep pedaling. If you're on the trainer for a good workout, coasting kind of ruins that. So they decided on a simulated draft effect which cuts the necessary power of a drafting rider by 25% so let's say you can go 20 MPH holding 200 watts by yourself. In a blob, you would be capable of going 25 MPH for the same 200 watts. You are combining the power of all the riders that cycle through allowing people to reduce their efforts a bit in the draft. So strong riders can get the blob to a high speed and other riders can hang in there because they get that 25% benefit. Strong riders put in strong pulls then drop back in to recover and the cycle repeats. The bigger the blob, the bigger that effect gets as there are more people to feed into that structure.
Hi! I tend to keep my difficulty level at 100% so that my virtual rides better simulate the feel (hills or fatigue) that I'd feel on the road. I am curious: 1) if a rider sets the difficultly to 0% and climbs Alp Du Zwift, do you get credit for the full elevation? and 2) if you are in a Zwift workout how does this setting interact with ERG mode?
Hi! Good questions. Yes, you will get full credit for any world elevation irrespective of your trainer difficulty settings. Erg mode is also independent of trainer difficulty, so if it is zero or 100, ERG mode won't change at all, neither will incline mode in a workout. It only impacts free-riding in Zwift 🙂
Great explanation for this audience, thank you for the effort and the willingness to endure the slings and arrows of outraged Zwifters. A disspassionate explanation with the exactly proper admonition to use the information as the user sees fit. Zwift is wonderful because you can you use it as you see fit. I don't care about steering and never will. I don't get outraged when a group ride of over a hundred riders splits because I suspect most everyone can find a smaller group to ride with that is much more attuned and aligned to a shared goal for the ride - which I think is wonderful thing actually while others can't handle diversity and demand punishment for those mad explorers that will always want push beyond the fence to "explore strange new worlds; to seek out new life and new civilisations; to boldly go where no human has gone before". You are an oasis of reason and I salute your efforts.
can you liken the slider to changing out your cassette -? I read or heard that mentioned someplace = so, if you have an 11/28 cassette - the slider at 100 is that 11/28 on your 10% grade - but if you drop it do 50% it is like swapping it out to a 12/32 or something like that - or is this the "myth of gearing" that you reference -?
and in reality, doesn't changing out your cassette also kinda "flattening out the world" as you mention - :-) - I mean I sure as hell have done that for really hilly events -
Thank you. Good explanation!!
Well explained 👍🏻
Thank you. I didnt realize my setting was at 50%. Moved it to 100% today. Although the hills now fell harder, when I stand up and put more power on it seems like I am accelerating faster now? Is that because before a 10% grade for 250 meters was translated to a 5% grade over 500 meters? I even had a couple KOM prs today even though I moved my difficulty to 100%
It won't change your speed, but your power execution is probably improved. Many people are capable of reaching higher numbers on climbs because that forced inertia effect. While it feels easier to keep consistent power on the flats, many power PRs are set on climbs because that resistance is begging for more torque, and people oblige.😉
@@EverythingIsPhotogenic Thank you. So in my prior efforts up alp du zwift @ 50% TD i was able to do a PB of 55 minutes. Was I effectively cheating at the 50% setting?
@@robfetty8637 do it at 100% and compare the results
I agree that the 100% setting gives the most realistic gradient experience for Zwift. In my riding area, we only have one "steep" hill that averages 9% for 300m. My trainer simulates up to 18% so I have mine set to around 60% to better "mimic" what I would expect to see in my outdoor experience.
Excellent video, thanks. 👍
Where is this resistance slider? I checked settings and there is no slider for trainer resistance.
Is one way of looking at this to compare Average Power to Normalised Power (i.e. NP as defined by Training Peaks)? When trainer difficulty is set to zero, you're effectively riding a flat course so there will be no requirement on the rider to change intensity throughout the ride. Therefore, in a perfect world NP and AvP could be the same. However with TD set to 100%, the changes in course profile throughout the ride will necessitate intensity changes so NP > AvP (as is usually the case). As NP is a measure of the true physiological "cost", if a rider is riding at their maximum intensity throughout a ride, i.e. max NP, then for a ride where TD=0, the AvP will be higher than the same ride where TD=100. Therefore the TD=0 ride would be completed in a shorter time (for the same average power), i.e. faster and advantageous in a race.
Or am I talking nonsense??
PS - Sarah, I hope you are recovering well!
Wow! That was the greatest, most thorough scientific explanation of the difficulty level I have yet to hear! Thank you for your explanation. As you say, there is a ton of varying information out there. Truth be told, I have taken a safety position and moved the level to 75%. Today, it will move to 100. Thank you so much for your awesome videos!
Two months of riding in Zwift with a dumb trainer and Assioma power meter pedals, Just purchased a Saris M2 smart trainer thanks for the great explanation Trainer Difficulty. Please do a video explaining ERG mode.
Great video, can you address height and weight doping and the benefits gained by using a false height and weight?
Weight doping is pretty straightforward. Your speed is built on watts per kilogram on climbs and raw watts on flats. If you lower your weight, you will give yourself a mathematical benefit by going faster for the same number of watts. Height doping is a little more tenuous, it's there, but I'm not clear on the math - or whether Zwift has recently adjusted that. Chris Pritchard experimented with it though, it's pretty damming. Here's the link
th-cam.com/video/w4BI1WwhL8M/w-d-xo.html
@@EverythingIsPhotogenic thanks Sarah
If you use TrainerRoad to do structural winter training using erg, how many times do you think you change gear??
If you’re using erg on Zwift and doing workouts it’s the same.
I race in the WTRL series and we’ve come to the conclusion a low trainer difficulty is best to race with. 100% difficulty will have you smashing through the gears on something like Titans Grove, constant ups & downs. The lower setting actually feels more natural imho.
I don't change gears at all in ERG, that's a key point of ERG, to eliminate shifting. ERG is intended for structured workouts for power development not real world simulation. It is common in racing to turn TD down it removes the undulations and people don't have to endure power losses created by shifting or endure the high torque output required by steeper grades, cadence can be more adequately managed at the riders discretion. It's not indicative of the real world or real racing as you would be required to shift for those same gradient changes in real life. The draft doesn't reflect the real world either making Zwift it's own unique racing format. People can race however they want, I just feel they should lock out the setting as they are for sanctioned events
Great analogy. I’m new, about 3 months in to cycling & Zwift. Changed to 100% a few weeks back, much better experience. I feel it should be locked out for races, and until it is - shall lower it to somewhere between 40-50% just to know I’m not screwing myself.
Does that mean that on a trainer with 10% Max gradient (Tacx Flux S) at 50% difficulty it still increases resistance when going past 10% in Zwift?
That's a big part of why the default is 50% to accommodate less capable trainers. That way you'll still get some added resistance as the road continues to point upward. The calculations will be the same, it will just be a matter of when you max out. So if your trainer maxes out at 10% it will stop adding resistance on a 10%grade at 100% difficulty or a 20% grade at 50% difficulty or 13% grade at 75% difficulty etc etc. The game doesn't really know your max trainer capacity when it does the math and sends the signal, the trainer just eventually maxes out and can't do anything with signals that ask it to add more brake
Great explanation but I have a question: if turning the trainer difficulty down "flattens" the climb shouldn't the length of the climb be affected by trainer difficulty: a climb at 100% TD should be shorter in length than the same climb (flattened) at 50% TD ... Yes or No
That's not how the algorithm operates. It's intended to make sure all riders cover the same distance without affecting speed. It's intended to make climbs more attainable without penalizing riders with additional distance.
@@EverythingIsPhotogenic well then clearly turning down TD in a “climbing race is clearly an advantage. Just using myself as an example ... I’m a bigger rider at 80kg and I can maintain a swift high cadence up to about 6%, I begin to struggle at 7-9% & start to wonder why I ride a bike when the double digits appear. Clearly, having TD at 50% on a 12% climb plays to my strength while 100% TD would be a miserable slow grind. Thanks for the response.
@@kaiyu4001 what you say makes sense ... now I’m completely confused 😱😱😱
No, if you maintain the same power you'll climb in the same time. If you can't maintain the power your speed will drop so your time to climb will increase but the distance remains the same.
Hey, great explanation. I’m on the trainer with my gravel bike that only has 40T front and when not doing a program I feel it’s very hard to do any event or keep up with someone because I run out of gears. How do you solve this?
Without having a training cassette that is suitable for the gearing you're looking for, you're probably going to need to use the difficulty slider. It won't provide the realism, but you'll still be able to perform the effort without having to struggle through higher torque execution of power.
@@EverythingIsPhotogenic I already tried that and it’s not a solution, as soon as you hit 0 grade the power drops to less than 100 watts
@@JoseSorianoPhotography You have some sort of issue with your setup then, Your power is a function of your capability as a rider and has nothing to do with trainer difficulty. If you are putting out more than 100 watts and your trainer is transmitting less power than that, then you need to get in touch with your trainer manufacturer for troubleshooting.
@@EverythingIsPhotogenic there is no issues. It’s just the transition, I’m a heavy guy and on the hill I have the resistance to put power, as soon as I hit the flat with that gear ratio I have to spin around 95 plus cadence to generate some power. I have no issues on the uphill at all. Any trick? I know this is a known issue
@@JoseSorianoPhotography I must be misunderstanding your problem then, because there is no "known issue" or trick that I am aware of that forces your power to drop. That is driven by your physiology and ability to apply power. The resistance is going to come from the trainer, and that will come from trainer difficulty. If you don't feel that there is enough resistance on the flats, you need to turn up trainer difficulty closer to 100. If you still don't have enough resistance, you may be under-geared. I find that hard to believe if you are on a 1X gravel setup, but it is a possibility. I really don't see a situation where you would be in the 40-11 at 100% trainer difficulty with no resistance - failing a malfunction in the braking mechanism of your trainer - it may be applying only a fraction of the resistance you need.
Great video. I’m racing Zwift for a few years and I think that everyone should have the trainer difficulty at the same level for the race. If you want to put down for training it’s fine. But for race should be 100 % difficulty to be more realistic.
I find these videos to be interesting. It still doesn't make sense to me. I find it interesting that Zwift's eSport rules specify the following: 2.5.3. Smart trainer difficulty must be set to 50%.
Made a big difference setting it to 100%. There is to gain in strength for both climbing in the flats. But it will really gauge your fitness. And it will compel you to change gear. Real riding is in play now. Thanks Sarah
So i'm not sure if I missed you mentioned this but does the setting on trainer difficulty also affect training plans and workers outs? Or just racing?
Just rides in simulated environments so free rides and races. Workouts are done in static resistance or ERG mode
@@EverythingIsPhotogenic By the way are you going to make a video or are you going to comment on the Dylan Johnson TrainerRoad issue?
@@lawor8 wasn't really planning on a video. I see this as right up there with the Keto debate. The reality is that you can find science to support the trainer road approach in just the same way he used science to promote his own chosen methodology. TR has added some context to their high volume plans that have clear opportunities in their podcasts that address many of Dylan"s concerns. I'm not really interested in the loyalist debates on TH-cam, we all have our preferences and methodologies that work for our needs and schedules. I'll put it this way, both sides have their blind spots. I like TR but I take the time to understand the science and listen to my body. If the plan is pushing me toward burn out, I step back - the ride prompts in the platform encourage that kind of intentionality. TR serves up free education to augment the one size fits all plans that the platform offers, to help the rider to tailor it to their needs. I like Dylan, and I respect his research but I think his video was a bit of spews for views, slamming on a program based on an unpaid overview with screenshots from the site. Sign up for a month, dig in, give specific examples and there might be more credibility there. He threw shots at anecdotal accounts of success with the platform but thought nothing of using anecdotal accounts of burn out to support his thesis. Its disingenuous. That's my two cents.
@@EverythingIsPhotogenic Yeah I like your reply. No need to take sides. No matter what methodology you have to listen to your body. just to respond to something you said however. Read the comment sections. I stopped counting how many people stated that they were burnt out with TR if they followed the plan to a "t". Personally what I find more productive for me is understanding the overall guiding principles of progressive overload and that you have include the IF ( intensity factor) and TSS that life puts on you and add that to your training approach and plan. That's why I just create my own work outs now in Training peaks and move things around based on the IF and TSS that life gives me. As mature rider also I accept that I will progress a lot slower that a 25 yr old.. . But it's the IG life so It seems like people only post the HIIT/VO2max workouts when truly zone 2/3 also build fitness. And for sustained fitness you need alot of Zone 2/3. Oh well. Thanks for sharing. Just want to see how TR is going to address the criticism. Especially Nate and Chad who are both very opinionated.
I think the zwift slider is fantastic. I’m an older rider I want to be able to train for fitness without wrecking my knees.As for realism I’ve never had an indoor setup where out of saddle riding feels realistic,no sway makes for more of a stair machine technique .Im sure if I put the difficulty slider to 100% I wouldn’t be training 6 days a week.Im not arguing with anything you said , but if the anti slider brigade got their way ,zwift would be less accessible and lead to more long term injuries
Very well said ! Just the other day someone with sore knees asked for help on zwift companion, I answered to lower his/her difficulty setting, and yes I said it's like getting extra gears. Maybe not technically 100% correct, but close enough in two sentences :-)
Who is that beast C. Robinson? 281 Watts @ below 130 bpm. Either he has got a very low max heart beat either he is VERY strong. Nice explainations BTW.
Slope flattening and changing dynamics of the terrain is correct.
Resistance and trainer difficulty are intimately connected, I wasn't sure if you're suggesting otherwise. At higher trainer difficulty (or realism) settings, you feel the higher torque to turn. Consequently, you shift gearing to a bigger cog in the back to make it easier to turn. Resistance/torque to turn has come down. And aligning with the paper you linked to, riders tend to re-select a different gearing to where they like their preferred cadence to fall within. Possibly that's an in-grained way to activate the right type of muscle fibers optimal with metabolic expenditure. It's all in the brain/neuro-muscular system.
I think where the analogue of "virtual gears" comes in is when you reverse engineer with some math the equivalent size of gearing you're in when you turn difficulty / realism down BUT maintain the same cadence.
For a given cadence, a 100% difficulty would have you sitting in 34 x 24 (let's say). When you turn the resistance down, and work the math out with the speeds your avatar moves at, the equivalent size of gear for maintaining the same cadence will be something like a 34 x 28 or a 34 x 32. The "virtual" gear is the virtual size of the rear cog. Unfortunately, some people confuse this idea with believing that someone has handed them a set of gears and made life easier. Despite virtual gears, they need to maintain the rate of work to meet a goal speed or goal time. Rate of climbing = v x decimal grade. A rider will not maintain rate of climbing if they do not maintain ground speed, simple as that. Consequently, if that will force you to shift your real gears it will detract from the virtual gear you calculated anyway. But if you don't change your gear, you have to increase cadence probably substantially and incur a metabolic cost to move two limbs at faster speeds in a circle. No free lunch.
@@kaiyu4001 Right. The end outcome seems to be the same.
But when all I'm doing is workouts in ERG mode, this doesn't matter to me at all right? Just wondering
Nope 🙂 everything is static. Actually, you might notice the flywheel/inertia phenomenon if you use the small ring in a larger cog vs a big ring and small cog. The flywheel goes faster in the big ring. Most people use ERG with a straight chain line which keeps things pretty down the middle.
Small ring straight line will also result in less pedal revolutions for a given wattage in erg mode, so less component wear in the drivetrain, although higher brake force in the trainer at a lower flywheel speed.
I am trying to get under 1 hour for Alp du Zwift. I always do the climb on 100% trainer difficulty. If I turned it down to say 20% would it make the climb easier thus giving me a much better chance of meeting my 1 hour target?
It really depends on your capacity to maintain power. To get up the Alpe in under one hour, you need to maintain 3.1-3.2 w/kg or better. If the increased torque demands of 100 percent difficulty prevent you from doing that for whatever reason, then yes, you could turn it down and control your power more steadily without the forced feedback and undulations that could push you above your threshold and burn matches. If you can't average that power with the lower torque and higher inertia, the trainer difficulty will not have any time benefit for you. It really depends on the rider. Many can put out MORE power on climbs than they can on flats, but again, the variability of the Alpe in particular is not the most conducive to holding a steady power/cadence like some of the other climbs.
It depends on what cadance you are comfortable with. I am comfortable with 65-70 and I like to push through resistance, so I choose a TD which accomodates me the best. But when you like high cadence and you are a typical time trial specialist, you probably are better of with a low TD. In fact you will win a lot on the flat bends in which you can accelerate and keep you speed longer. Anyway, the variability of AdZ is different than the real AdH. So a lower TD will match more with reality. But then again, Zwift is all virtual. So it really depends whether you are a typical climber like me or a typical time trialist what you benefit from the most.
What’s your Zwift user name so I can add you ?
How accurate do you think zwift calories are?
If your power meter is accurate than the calories are about as accurate as you can get in terms of sports measurement.
Another great video. Spot on with the insight. My take on Zwift, regardless of trainer settings......as long as I spin my legs, elevate my heart and breathing rates, enjoy it, and don't take myself too far away from the real road.....then it's better than being a couch potatoe.
With trainer difficulty set at 100%, if I'm going up a 6% grade and putting out 250W and Zwift says I'm doing 6 mph, and then I down shift but increase my cadence so I'm still putting out 250W, Zwift should still say I'm doing 6 mph. With trainer difficulty set at 50%, on a 6% grade putting out 250W, will Zwift say I'm doing 6 mph or will I be going faster than 6 mph because Zwift is translating that grade as 3%? If the setting of 50% makes me faster, there is a big difference between climbing Alpe du Zwift as 12km @ 8.5% (100% difficulty) and 12km @ 4.25% (50% difficulty)
No, turning down the trainer difficulty doesn't make you faster, your avatar speed is dictated purely by power output (and your personal weight and height settings). It can however make it slightly easier due to the higher flywheel speed smoothing out your power output
No your speed doesn't change at all. If you haven't checked out the first video, I address how the algorithm creates speed, but the short version is speed is based on watts, weight and grade - trainer resistance is built on grade and trainer difficulty. They work independently of one another.
Very well said. Personally I have mine at 100% because I’ve never been a strong climber and that’s what I want to work on. Don’t care about power numbers or speed or anything else. Just want to work on my ability to get up the climbs.
Whatever someone else does has no impact on me. I know there are plenty of people on Zwift that run a lower setting that are much faster and stronger than me.
Do whatever the hell you want in life and as long as you’re not hurting anyone no one should care.
Great work!
Is trainer difficulty irrelevant when doing a structured workout?
yes erg mode sets it to zero
Once again.... very good and comprehensive explanation. Kudos!!!
So the pro racers on Zwift, doing all the races. Are they allowed to race with 50% difficulty? Do they get checked?
The dial is locked out, I believe at 50% that is the last info I got from a reliable source.
New to Zwift I mainly mountain bike but ride road bikes to increase my fitness on the mountain bike. I only train on 100% in Zwift to simulate real world riding because hills don't disappear in the real world. I have noticed through the punchy rollers on Zwift having the trainer set to 100% really hammers the legs much like the real world would do I am constantly shifting sometimes spiking over 450 watts to crest the top for the same cadence to keep my speed up then backing down to 250 once it flattens. Muscular fatigue over a long distance is real and you got to train for that imo or you could be surprised when you hit the open road. Like you said if you want to play Zwift like a game great but if you want to train for outside do yourself a favor go 100%. Even if you have more gears on your road bike vs your trainer it will only make you stronger.
isnt a starting grade of 4% that changes to 8% a 50% change in grade not a 4% change?
it is a 4 percentage point change. While it is a 50% change mathematically, that is completely irrelevant to physiology. The body doesn't process gradient change in percent increase, it process gradient in slope. We don't measure gradient in degrees so it needs to be discussed in percentages.
Thanks
If you ride road to sky at 100 percent difficulty you would climb 1055 m. If you ride with your difficulty setting at zero would you still climb 1055 ?
In the game, yea. It's arguable whether or not the muscular recruitment would be commensurate with 1055 meters in the real world - which is the crux of climbing and why it is difficult. If you ride a heavy enough gear, you could get a similar effect, although the inertia would likely be a bit different depending on the type of trainer. The power to speed ratio would remain a constant on Zwift, which is what most people are concerned with. If you're asking if meters climbed in Zwift equate to real world meters, that is a long standing debate, but the closer to 100% you are, the more likely it is.
The TL;DW explanation dumbed down even further. 50% TD makes riding 39x25 up a 10% grade feel like riding a 39x25 up a 5% grade. It doesn't make riding 39x25 up a 10% grade feel like riding 39x50 up a 10% grade. Entirely different scales.
Also as zero-percenter, my personal take is that indoors I am working mostly on that aerobic baseline, especially in the absence of outdoor racing. If I can maintain 300W for 60min regardless of virtual terrain for training purposes, it's overall more beneficial than occasionally slogging it at 285W because of lower moment inertia or grade changes causing micro-accelerations. When it comes to muscle activation, that progress can be made in a couple of weeks. I actually know some active climbers who do worse with lower TD, so in the end there's different answers for different adaptations and goals.
the above will rely on the amount of fast twitch muscle fibres you have; everyone is different someone with lots will climb well those without will not; as a rule low cadence stuff is fast twitch time as well as activating your slow twitch.
Inertia still is a real concern if trainer difficulty is locked at 100% - The rider with the most expensive trainer has an advantage instead.
More $ usually gets you a heavier flywheel and thus more inertia. Some expensive models even have motors that actively spin up the flywheel when descending. You benefit from that inertia on the next incline. This can be significant when riding 'up and down' terrain.
Steep inclines on cheap wheel on trainers really suck because the thing looses speed between each pedal stroke. Just not enough flywheel inertia. It can be much worse than in the real world and it often results in tire slip.I think on a device like that is a good idea to use lower TD.
I like being a good egg. Thanks for having us
The best explanation of trainer difficulty I've heard since Zwifting, excellent. Could you clear up one little thing that I read about? I read that the factory-set gradient data sent to the trainer is based on an algorithm based on a rider weight of 80kg. So an 80kg rider riding up a 10% gradient with trainer difficulty set to 100% gets the exact resistance on their trainer that an IRL 10% gradient would give. Firstly is this true, and secondly what if you weigh less, like me at 55kg, should I adjust the TD down as a percentage of 80kg? Equally if you weigh more than 80kg if this is true then these riders are potentially missing out on achieving the on-screen gradient. Thanks
I believe the algorithm is built on a 75kg rider. To be honest, I don't think it is a key element given that zwift doesn't account for wind or rolling resistance. I'm 51kg and find that it's pretty true to form for real world gradients in terms of speed and resistance feel.
@@EverythingIsPhotogenic Thanks for the reply, 100% TD it is then! Ride On.
The watt/kg is the same at 100pct as I use easier gears. But im going slower. Its that simple. But yes it does feel harder but not twice harder
Great explanation! Loving this geeky stuff and pretty funny.
Dunno who C.Robinson is, but damn that dude is a beast
Simply put, TD @ max is more difficult plain and simple. Tougher to get up hills and typically you will get tired faster. You can have all the gears you want, it doesn't matter speed won't change. You'll also have to spin up your cadence every time you shift up to a smaller gear to match the power output and at a certain point it's exhausting. Do a quick hilly race at 50% vs 100% and it's very obvious.
Agree that momentum and inertia are where the virtual gearing argument falls apart. Good video. Interestingly though, when I trained on Zwift with a power meter and a dumb trainer, the hills still felt harder than the flats, so some of it must be in your head!
Funny you say that... I have a (relatively simple) smart trainer (Tecx flow), and even when I'm doing a planed workout in ERG mode (where the trainer forces you to hold a set power and ignores the road gradient) I still "feel" some difference when I'm climbing or decending. I guess just the visual of going downhill and seeing everything goes by fast triggers the memory of a real world descent and I somehow think that it's easier, and even that I should increase cadence!... Even if I'm still holding the exact same watts I was suffering on seconds before during the ascent! Hahah The brain can trick you a lot, but the legs end up feeling it and bringing you back to reality :P
ok, here is my beef. I ride with two others in meetups and we are all around the same skill level when out on the real road. My Madone is running a rear 25, other guys 28 and 32. When we ride in Zwift, if we all go at 100 on the difficulty, I can't come close to hanging with those guys on steep climbs, I just run out of gears. They will bitch and call me a cheater if I compensate and drop the difficulty a bit and try to match at least the 28 gearing. Should I suck it up and buy a different cassette?
If budget isn't a constraint, I would get a 11-28 or 11-32 105 or ultegra between 45 and 60 bucks. It will better simulate road riding for you and the better control over gearing actually can help performance. It will last you at least a couple years so you will get your money"s worth. There's a time and place for turning the slider down for sure, but if you're an outdoor rider, the investment is worthwhile. 11-25 is almost unrideable on Zwift in my opinion, unless you're sticking to the flats or dig a 50-60 RPM cadence. But don't feel bullied into buying gear if it's not right for your budget. We all have bills to pay and people are not in great financial shape right now. It's not that you can't use the slider to offset inadequate gearing, I just want people to understand why it's really not a gear selector if that makes sense, mostly so people don't get out on the real road and have a WTF moment being unprepared for the torque requirements of hills. Hope that helps.
not all turbos are the same do all your devices go up to say 18 -20% gradient; some max out at say 8 % for example
You're awesome......love your brash delivery style. Thanks again.
Refreshing to see someone who gets it right. I've ranted about it not being virtual gearing too many times :D
Thanks again for the detailed discussion of this - everything you've said makes sense to me!
I've read articles where smart trainer manufacturers are proud of their repeatability, duplicating the dynamic loads you experience on the road in every respect possible. If Zwift reduces the % grade given to the smart trainer, and then does post-processing to scale down speed / distance, I'd expect realism and accuracy to suffer under dynamic course profile and rider conditions where kinetic energy (exponential: 1/2mv^2) changes happen suddenly. Some questions that come to mind if reduced TD flattens the route:
* Are you less likely to shift, then stand up and dance on the pedals where the course otherwise pitches up a lot?
* Will you need to do less shifting overall? Lots of shifting can cause fatigue, and momentary drivetrain dropouts that can add up (particularly if you drop the chain ;-)
* Are you at a *disadvantage* with lower TD on an uphill sprint, where sudden speed (hence kinetic energy) increases from higher (trainer-perceived) velocities are required?
I can see where Trainer Difficultly could behave just like virtual gearing for climbs under established steady-state conditions (constant grade, constant rider power/torque, etc.), but this doesn't happen in the real world! I agree that TD needed to be locked for all racing events. Kudos to Sarah for helping to dispel the notion that they are equivalent...
Pretty good explanation which should dispel some myths! Even though, as a trained mathematician, I would prefer you to carefully distinguish between "percent" and "percentage point" in your video :) As in "if the gradient increases from 1% to 2%, it an increase by one percentage point, a hundred percent increase".
This is directed to a general audience. Percent change would complicate matters, most people aren't fixating on an omission of one word. They also aren't fixating on the simplification of the inertia concept and my omission of the term kinetic energy and delving into the specificity of that concept 🤷🏼♀️
ill agree with you if we were all riding single speed bike , were not > if your doing a race , youre going to have to upshift to keep up with everybody on a climb if you have it at 50 % , and you'll probably downshift if youre at 100 % (unless youre riding a single speed )
That's not how things play out. People don't upshift at 50% they maintain a higher and more comfortable cadence while people at 100% may run out of gears. This has nothing to do with single speed.
I ride team time trials with a difficulty of around 10%. This gives an increase in power of roughly 5% per 1% increase in grade, which for most courses is the optimum pacing strategy. For everything else I ride with 100% after watching your first video
The main reason I do this is to not have to think, as I spend most team time trials at 95%+ HR!
@@chrismccarter6875 Totally fair, that's a perfect reason to use it!!
Thank you as always for the info. I am a old fat cyclist that has been riding and racing for 40 + years. I love racing on Zwift but struggle with technology.
You failed to mention the effect on avatar speed altering trainer difficulty has. Zwift has to penalise you some how when you alter gradient bias so it slows your speed vs effort to compensate.??
I didn't fail to mention it, I did a whole video on this and linked it in the description. Speed isn't affected in any way. It's only resistance feel. Speed is only built on power and world gradient.
Speed is only built on power and world gradient??? What does that mean? What I’m saying is the effect of lowering the Trainer difficulty in theory makes the rider think it’s easier but Zwift has to compensate some how and does so by slowing your avatars. Ride a 4% incline @ 300watts @ 100% then the same 4% @ 10% difficulty at 300watts and your avatar will be going slower. That’s my experience anyway.
@@terrysandoe3531 that's not accurate. The speed at 300 watts at a fixed grade will be identical regardless of trainer difficulty. Difficulty only affects resistance at the trainer. The speed of your avatar in the world is only calculated based on rider weight, gradient, and power. Nothing else.
Terry Sandoe I understand what you're saying (I had the same impression) but the proof that the speed is unaffected by TD is right here in this video. Check it out; it is interesting to say the least th-cam.com/video/_mjAZyhOlt0/w-d-xo.html
I think the reason people think of trainer difficulty as virtual gearing is because they just think about the ascents.
There is only one single route on Zwift I can think of where you could think of trainer difficulty almost the same as virtual gearing. And that is the Ven Top. The reason for that is the lack of flat parts and no fast gradient changes. The experience for turning trainer difficulty down a little should be around the same as equipping a cassette with easier gears.
However, look at other climbs. On the Alpe there are many flat parts in the corners where you spin out at a high trainer difficulty. On a lower difficulty you can keep putting out power without shifting. This is the same on many climbs, as most of the large climbs have many steps with flat parts. On those climbs, a lower trainer difficulty already does not work the same as equipping a cassette with easier gears, so is not the same as virtual gearing.
And look at more extreme examples. Small climbs followed by a descent, like the legsnapper. If you reach the top at 100% trainer difficulty during a race and need to do the required shifting to be able to put out power again, you'll probably lose connection with the group. Most racers, myself included, turn the trainer difficulty down to 30% or lower during races. Those low settings really flatten the road, but are needed to not get dropped after fast gradient changes.
As always great vid! Such clarity to an ever cycling(😉) argument about zwifting and real road riding.
After watching some of your vids on the difficultly settings, I decided to up it to 100%.(was on default) because I felt I was cheating myself. Now, I noticed I try so much harder to maintain a decent cadence going up the alpe or radio tower, and surprisingly my PB has improved.. even on first attempt. Definitely feels
harder.. like when I finished the 4 horsemen, my legs were hurting for the rest of the day.
For me, having at 100% just makes the ride a little more realistic to what it would like out on the open road. But there is definitely a difference between Zwift vs out doors. There are no variables like wind, temperature changes, friction, and potholes lol to deal with. Even though I can ride mile after mile on Zwift, I just can’t do that on my 56 mile commute everyday.. it’s completely different in my opinion.
Great work! 👌 stay safe
With TD in Z race, you will be 100% dropped in decending. Of course you also will facing some disadvantage in climbing, you will cost some time to change gear and get slightly dropped (but managable). And while decending while everybody is attacking in downhill and you are strugling to find a gear to follow (if any of your biggest gear still can provide you some resistence.... So try to use no TD or very slight TD in Zwift Racing, and only use TD for solo and climbing training by yourself alone.
Excellent explanation. I’m not sure why someone would want to adjust this and expect a good training outcome.
Because not everyone has the same training goal. You get a training benefit regardless of the setting position.
Here's a correction for you. You said Power is Force times Velocity and linked that to wheel velocity and the flywheel.
Power is Watts.
Watts is Energy per second.
Energy is Force * Distance.
Power is Force * Distance /Time.
Distance is the distance the pedal moves, not the wheel or the bike. Distance/Time is RPM.
(with a factor of 60*(2*Pi*crank) and uneven pedaling))
Power is Force times RPM.
If you double the RPM and exert half the force you'll create the same power and the same bike velocity.
That's not a correction, that's a word salad to pretend like you've presented some kind of mind blowing argument. Watts is a unit of measurement that measures power. Watts are joules per second. Joules are a measurement of force Newtons x meters. I didn't say the velocity was at the flywheel I said it was at the crank and that it was assisted by cassette speed which is... Wait for it.... Impacted by the flywheel **gasp** which means you'll potentially double your cadence and exert half force... And what does that mean? Oh... Less drain on your type 2 muscle fibers and increased repeatability... I've done 3 videos on this and discussed the physics both in the videos and pinned comments in excruciated detail. I'm not going to be corrected by some half baked comment that does nothing but restate my argument and pretend like it somehow proves me wrong. Try again 🤣
owned :)
@@kblades9409
From the Photogenic video transcript 11/28/2019 >>>>>
19:50 yes there is an advantage at riding at
19:52 a lower trainer difficulty yes you have
19:55 to produce the same amount of watts
19:56 regardless of your trainer difficulty to
19:58 be able to keep up with the group but
20:00 your repeatability and your muscular
20:02 fatigue will be drastically different
>>>>
That sums up gearing too. If you shift to a lower gear
You still have to produce the same watts to keep up,
Watts over the same time equals same Energy expended.
Gearing or trainer difficulty have the same effect.
(YT inserts unwanted hyperlinks!)
@@DouglasKubler ha ha trainer difficultly at low setting allows folk to use gears they never would up a climb some one at 10-20% could in essence go up the alp in a 53 - 11 at high cadence. you try doing that up a 10% hill climb irl; utter bollox. you keep believing your own rhetoric chap. try going up a 5% hill irl at mid zone 4 power in 39-28 sprocket, come back and tell me what cadence you had to achieve to do that
Great Vid and explanation. Now tell the rest of the story... There is no “virtual” advantage. Only a physiological advantage - which is a real world liability.
Cycling is like Golf in this way - use the identical swing and change the club to adjust distance. In cycling, keep the same cadence and adjust gearing based on grade. (And in no other way that I know of!)
In Zwift, the virtual distance traveled over time (a measure performance, like winning) is based on the (secret?) equation using w/kg, road grade, virtual bike parameters, and magic. On a virtual grade (say 10%) at steady effort (say 250w) and TD=0% - the resulting virtual road is now flat. But the credited speed/distance isn’t not the same as riding at a virtual 0% grade (flat) at the same effort (250W.) It is lowered by the magic Zwift formula for any given virtual grade.
A second identical rider at TD=100% will need to shift to a easier gear to maintain optimal cadence for the 10% - and will have the exact same speed/distance as Rider 1. There is NO time/effort benefit for distance traveled.
If the virtual road is wildly fluctuating - Rider 1 might as well be staring at a brick wall putting out a steady effort until the course ends. Boring, highly efficient, and no connection to real riding. Rider 2 is experiencing a lot of cadence and gear changes - which is much more real. For identical efforts, they still have identical times. The reason to lock TD in events is simple - steady efforts are easier physiologically than surging (intervals.) IRL - you will hit the 18% grade, drop it into your easiest gear, and barely be able to crank out 55 rpms. Learn to be ready for it.
I did "tell the rest"of the story." In the original video that I mentioned within the first 15 seconds of the video and linked in the description with a disclaimer in all capital letters.
@@EverythingIsPhotogenic Nailed it. I did not see the first video. Keep it up the great work... more knowledge shared is better for everyone. TD is about making Z more accessible as a entertainment-fitness and that increase the total users on the platform. That’s a win for everyone.
As Z moves towards ‘eRacing’ , and we look toward more cycling realism in general, there are many things which are very unrealistic. Momentum is a big one. A topic for a video perhaps.
While riding in a virtual group ride and you stop pedaling for a few seconds to pick up a dropped towel or adjust your shoe - you’re going out the back and you may never get back into the group. IRL - you may drop back a few positions and a quick small effort you will slot back in. Z is very unlike riding in a real group in this one way. It’s not about the KE in the flywheel - it barely slows down and you’re back on it in seconds. Something else is going on - overly rewarding very steady efforts. In a Zwift race, my power output is very flat. In actual races it’s all over the place with a surprising amount of time in the 0w-100w range. Zwift isn’t ready yet to teach how/when to save/use energy - the best and most important aspect of actual racing and “race-training” group rides.
I will point out that in a group ride at 35mph (56kph) on the flat, and if you slide out of the group completely into the wind and stop pedaling for 4 seconds, that is exactly what will happen. But not at 25mph and staying completely inside the group.
(Minor - you said Z sends a request the trainer to simulate a grade. Is this true? Pretty sure Z decides on the effective resistance at any given moment and can only send resistance to the trainer. The trainer doesn’t know my weight, bike weight, road type, etc.)
I got a wahoo kickr and a treadmill for zwift, I never take it serious when riding and people talk about their achievements on zwift. I just assume everyone is cheating and it doesn't bother me. Though it's a reason why I stay away from races. On zwift it might give you an impression that 50% of the people their are advance to professional which is not my experience with triathlons. In real life advance to professional level athletes makes up like less then 3% of a population in a race. But in zwift it seems like that's not the case.
Ride on!
Kudos to whoever you have riding behind you during this video. 281w and only 133BPM and only looks to be in zone 2.
Also be aware, Per Zwift themselves...100% setting is based on a rider weighing 75kg.
I have no problem with the explanation at all. However, I'm not sure I agree with you about who this matters to. You claim this matters to people doing serious training but not those playing it as a game. I disagree, nobody doing serious training should be free riding around zwift's hills and putting in real world efforts as their training. They should be riding to time and power in intervals and the terrain should be, largely, irrelevant. When they are free riding, they should be hitting lots of Zone 1 (if recovering) or zone 2 (if building endurance) and they shouldn't want the hills they come across throwing them out of their planned zones. People playing the "game", who aren't serious, if they think it's "real" effort and care about the pride of "climbing" Alpe de Huez or Mont Ventoux, they should care (somewhat).
That's not entirely accurate. If I am training for a hill climb or mountain race in April and my weather prohibits outdoor training, I will get far more value in performing self managed intervals or hill repeats to train pertinent muscle systems and cadence. If your training methodology doesn't align with that, then that's fair, but to say serious athletes won't free ride, is a disingenuous generalization.
@@EverythingIsPhotogenic ok, but if people are using zwift to seriously train for those events, even if they did think it was virtual gearing, and even though it’s not (which, as I say, I agree with your explanation), they really shouldn’t be using any form of flattening/gearing that they won’t have on said hill climb/mountain anyway. Seems odd that anyone would think a good way to train for that would be to put a 50 tooth cassette on the back, that they won’t have on the day, even if that was what it was the equivalent of.
I think if you take the extreme TD cases it becomes clear. Go up Alpe du Zwift at 0% and 100% TD. At 0% it becomes a perfectly flat TT course. Find your perfect gear for your optimal cadence and hold it. If you're in good shape no need to shift. At 100% TD there is no way you can avoid shifting going up Alpe du Zwift. Frequent shifting is inherently inefficient no matter how you look at it. Thus based on shifting alone 100% TD puts you at a disadvantage ...
interesting about the shifting; when im doing the alp or bolognia i set my gear and never shift at all; on the alp i use cadence to increase or decrease my power. on an undulating course that is different but even then i tend not to change to much and use cadence. im running a 54 q ring tho with a 11 -28 cass. a nice 50 rpm up bolognia is a killer; im at about 65 TD would not get up that at 100% on that gearing :)
I saw the video, and the original one, and the Chris Pritchard one, and then some ... Facts are facts, nobody can argue the facts. It IS more difficult (and more realistic) producing for example 250 W uphill vs on the flats, due to cadence, momentum, inertia ... But shouldn't we think of the speed being affected by ... staying the same? If I put out 250 W on an 8% slope IRL I will go slower then I would putting out 250 W on a 4% hill (trainer difficulty at 50%), but in Zwift the speed stays the same.
So there must be something extra in the formula/algorithm. I think that's why a lot of people still compare trainer difficulty to changing a virtual cassette. I agree that there's no cassette in the world that would make a 20% hill feel like a 10% hill, but where a live the world isn't as varied as in Watopia either. Neither are there cassettes that would affect slope-changes. When you hit a difference from 8% to 16% around a hairpin or something, that's a lot. I agree that you can't take away that difference using another cassette, whereas you can in Zwift by changing TD.
For the record, my TD is set at 100% and will stay there. So this I'm not trying to protect my ego or anything. I just think that there is still more nuance to it. The @GoZwift people on Twitter approved the comparison to the virtual change of cassette when I asked them.
So ... I think that it doesn't JUST flatten the road, because then you would go faster.
Does this make any sense?
I covered a lot of this nuance in the first video and was sure to notate in the description that there is no impact on speed. It is flattening the road *feel*, but the speed is calculated independently of trainer resistance so you have two calculations 1. Speed = Watts/kg by grade with a little bit of CDA built in weighted for raw watts on flats and w/kg on climbs - this is done to control your avatar. 2. Resistance = Grade * Trainer Difficulty % and that is done invisibly and communicated to your trainer. A lot of folks don't realize that the trainer is not doing the work, Zwift is. Zwift tells you one thing on the screen and tells your trainer something else. I wouldn't say it's as much nuance as it is a wholesale fabrication by the platform from a programming standpoint. The original reason that Trainer difficulty was implemented, and the reason it remains at a 50% default was actually a throwback to the ubiquity of wheel-on trainers before direct drive. Most of those trainers had a max grade of between 6 and 10%. So if you maxed out difficulty and climbed the Alpe, at a certain point, the trainer couldn't add any more resistance, so a person would see gradient go up but it didn't match what they felt. As more direct drive trainers became accessible and affordable, the slider continued to have utility as the bulk of Zwift's riders are amateur and many of them are not committed cyclists. They are recreationally fit and do this for a good workout. Those folks are not capable of the output it really requires to climb epic KOM or the Alpe, but that slider makes it possible. Take for example a 100kg rider, maybe he is brand new to riding and has an FTP of 150 watts. He takes his bike and wants to do the Alpe no matter how long it takes him... 3 hours? Fine. He hits the Alpe and can pedal at a lower difficulty at 120 watts for hours and the game will put him at that speed floor of 2-3mph and make it to the top eventually feeling proud of his effort. If he put his TD at 100%, no dice. He won't get one pedal stroke. Nor would he on the real road. There is a minimum effective power it takes to overcome the gravity and inertia of a climb, even if you have the most aggressive gearing. Trainer difficulty allows you to bypass that lower limit because it's a multivariate calculation that involves independent tasks. It is very difficult to communicate this in a way that everyone accepts unfortunately. But if you really suss it apart, it makes sense. I have had the fortunate opportunity to have been on the platform from very early days. Back then the community was tiny, hundreds, and we had a solid pipeline directly to the developers through community groups. I have confirmed my understanding of this slider with them, so I am confident in my content, I wouldn't put this up if I wasn't, that would be disingenuous and lead people I care about in this community down the wrong path. Zwift themselves are flummoxed as to how to broadcast this idea to a "pedestrian" audience. They default to the 3 sentence version because that is sufficient for 75% plus of the riders, the remainder of us toil in the wind because Zwift doesn't just come out with an end all, be all TLDR version. I hope this made sense, I totally understood where you were coming from and wanted to put more context behind it.
That was well thought out!! I think it may help a lot of people out there. Like one other cyclist mentioned I keep mine at 100% to keep it as real as possible
Oh no! You have damaged six fragile egos who felt compelled to give you a thumbs down! THANK YOU. No matter how many times people tried to explain why they believe this is virtual gearing, something always told me no, that can't be right. My gut was telling me exactly what you explained so THANK YOU. Also 15:02, I agree with you,Teddy.
LOL That loud cry was Leo, he is camera shy but he yells like no one's business every time I make a video. Teddy's cries are pitiful, he sounds like a kitten, that may be partially why he gets away with his bullshit.😂
@@EverythingIsPhotogenic GO LEO!!!
Thanks for this video and the explanation. Those who think there is no difference are essentially saying that lifting a single 100lb weight is the same as lifting a 10lb weight ten times. On some physics-adjacent, academic level, it is the same. But in a workout situation, you are not doing the same amount of work in regards to your training. Still, if you are okay with this, and understand the effect this has on your workouts, then adjust away. And your observation that the feature is locked out for races, well, that pretty much says all you need to know. :)
Why do you think Zwift’s default trainer difficulty is 50%?
two reasons. One, when it was created, many smart trainers were only capable of up to 10 degree gradient simulation so they wanted people to still feel resistance changes when the world exceeds 10%. Two, zwift had a large "pedestrian" audience. Many climbs in the game are beyond the capabilities of the "typical" rider. Having the slider makes it challenging but achievable for most people after some rudimentary training.
@@EverythingIsPhotogenic Makes total sense -- thanks for the explanation! Random, but Zwift-related follow up q: If two people on two different Zwift accounts share the same trainer, will the trainer resistance always follow with whoever's account is actively Zwifting?
For example, Person A uses Zwift at 80% trainer resistance and Person B uses Zwift at 100% resistance. When Person A uses their own account, the trainer will always be at 80%, and the same for Person B at 100%. (Basically I'm clarifying that even if Person A uses Zwift 90% of the time, trainers don't take into account the historical data resistance level and auto adjusts Person B's settings as a result.)
@@DGOS2012 I think what you're asking is if the trainer holds the memory. So if spouses share a trainer and log in from the same machine what happens to the setting. I am 99% positive the settings are tied to user. They definitely aren't tied to the trainer, but I've never actually done the experiment to see if it would be tied to the actual machine it's played on. I am almost certain it would be stored in a game asset file by user so ir Mr. X likes 100% at 4K resolution with chat off, and Mrs. X likes 80% at 1080 with chat on, they wouldn't have to monkey with the settings, the login data would handle that. 99% sure but I don't have that personal experience. If you were to drive your trainer to your brothers house so he can try it on his own machine, then his settings would prevail for sure. The trainer stores nothing. I hope that answers your question
@@EverythingIsPhotogenic It does! Thanks! :)
@@EverythingIsPhotogenic and as you know and already mentioned the TD allows those recovering from injuries to still complete some of the climbs
Completely and utterly totally correct 👍
You just need to try and climb Alpe du Zwift @50% and 100%. Physiologically, they're just different mountains.
Isn't that the truth!
Tacx Neo has no flywheel and so there is no momentum.
The virtual flywheel in the Tacx Neo simulates mass inertia commensurate with the settings for trainer difficulty and grade. Whether it's mechanical or virtually (magnetically) driven, there is energy return at the cassette. You would not be able to pedal without it. You don't have to take my word for it... Coast and see what happens.
@@EverythingIsPhotogenic Show me what it gives me at 10 km/h during climbing the AdZ, I think it is very minimal and of no significance to power needed.
I agree with you when you say you have this effect downhill and on the first approach of the coming ascent, like on Epic KOM where you are able to maintain some speed for the last part of the climb. This is far from reality and also when you have set TD to 100% you still will have too much profit by this.
For me Zwift is already unrealistic in some aspects, like the one decribed above, but also when it comes down to variability of the gradients. Also the effect of change in gradient is more than in real. For example I have climbed the AdH multiple times and I can't remember that it changes so much in gradient all the time. After La Garde there are no real sections of more than 10% while in Zwift there are multiple sections of even 12+%. So indeed lowering TD will flatten the course, but probably the course is more realistic at 50% than at 100%. But these are my two cents as a typical climber who loves to push through resistance and likes to take te steep part of an hairpin.
@@aperdon7694 I can't "show you what it gives you at 10 km/hr" because it is contingent on the gradient and the trainer difficulty. The inertia will be different at 50% than at is at 100%. At 50% you will get more energy return and flywheel spin than you will at 100% holding power and cadence constant. That's how the trainers are designed to work. The tacx is not an exception to physics. You train how you see fit, but I won't engage in an argument surrounding the precise delta in flywheel speed and it's impact on muscle recruitment for an infinite number of variables to make my point.
@@EverythingIsPhotogenicMy point is that it is of no significance to the power needed to maintain 10km/h.
My experience is that the flat unrealistic bends in AdZ gives far more profit than any flywheel advantage giving you unrealistic accelaration for the next steep section. In real life I never accelerated to 20km/h during a bend at AdH, but at Zwift I actually do without any real effort.
My overall point is that Zwift is already unrealistic and also it is virtual. There is nothing realistic in Zwift, even not the the speed calculated. In real life I don't ride 30km/h at just 120-140 watts. Also I won't climb AdH in 75 minutes at 180 watts.
But anyway, I agree with the flattening part.
@@aperdon7694 I never said the power requirement changes. I was clear about that in both videos. My argument has always been about muscle utilization and the demands on the physiological system. Between these two videos I discussed fatigue resistance, repeatability, and the relevance of cadence to those two very critical elements of cycling. Higher trainer difficulty and lower inertia closes the range of self-selected cadence available to a rider, demanding a higher muscular load and less reliance on circumferential velocity - that velocity can be largely driven by the cardiovascular system with a muscle sparing effect. Momentum at the rear assists in that velocity. Circumfrential velocity is half of the power equation. The watts required to produce a given speed at the prescribed gradient will not change, full stop. To argue that here is a complete straw-manning of my entire premise.
I can't believe people are still hung up on this. Each to their own. But you're only cheating/beating yourself.
Mine is always set at 100%. I want to feel as realistic as possible & I know that Zwift is also a game.
@@kaiyu4001 I don't think it matters what cassette you use, you still push out the same watts regardless. Get on and enjoy the ride 🥰
If you do the experiment with the same power and the same distance with 100% and then 0% on trainer difficulty, the only thing that changes is the gear or cadence. Work and time are the same.
If you keep the same gear, the candence will be higher at 0%, if you keep the candence you will have to change the gear.
It is true that using the 0% appears to be making the world flat, but it also eliminates the descents!
Therefore, this explanation or the explanation of virtual gearing, are the same but from different perspectives
No one said work and tome change, my original video covers this and cadence in detail. Kinetic energy and inertia absolutely do change, thus this explanation. Gearing doesn't eliminate descents, nor does it change the percent change of terrain. The analogy is bad.
@@EverythingIsPhotogenic It seems to me that you try to justify that there is gain or loss by using the trainer difficulty, but there is none.
Also tries to justify that it is not virtual gearing, but it is a valid explanation.
@@hugosadhus I justify that inertial load creates a change in both muscular utilization as well as sustainability. Which is true. I included a research paper outlining just that. I am also justifying that changing a cassette on your bike will not change gradient changes on the road. A road that changes from 10% to 20% grade is a change of 10 percentage points. At 50% it is now reflecting 5% to 10% which is 5 percentage points. NO cassette on the planet will do that, period. It's not gearing. Zwift doesn't call it gearing, and I'm not going to perpetuate this illusion to feed ego or simplicity, it's wrong and defies science and physics.
@@EverythingIsPhotogenic I didn't say otherwise, nor did I say you were completely wrong ... I think the problem with egos is not mine, best regards '-'
@@hugosadhus I believe the problem with your position is how you explain it. The video is straight forward but your issue with it is not. What are you challenging?
Nice explanation. Of course like everything in life these days there will be 7.5 billion different opinions. Ride Hard, Ride Fast and have fun. Ride on.
Love your videos! but your keyboard is on adderall