Zwift Trainer Difficulty: There’s one more thing to know….descents!

Zwift Trainer Difficulty: There’s one more thing to know….descents!


Today’s video is about the trainer difficulty setting within Zwift. The most asked about and the least understood setting within Zwift There’s more to it than just going uphill Now before I get to the details of this video be sure to hit subscribe on this channel It really helps it out and helps me keep producing content like this Okay onto the details and the trainer Difficulty slider or the setting within Zwift. What you need to know is the trainer Difficulty slider or difficulty setting has no impact here in game It’s only what is sent to your smart bike or smart trainer in regard to the gradient So for example in Zwift if my trainer slider was set to maximum and on screen It said 10% then that’s what Zwift sends to my smart bike or smart trainer It will simulate a 10% gradient Now if I was to set that slider to halfway such as 50%, the trainer difficulty in game no change whatsoever The Avatar still has to ride up a 6% grade However, once we’ve sends to the trainer or the smart bike is halved, so I only feel a 3% climb However, there’s more to it than that and The downhill is a little different. By default Zwift will send only half of the negative gradient To the smart bike or the smart trainer and that’s when the slider is at maximum so if I was riding down a -10% gradient Zwift will only send -5% to the smart bike or the smart trainer. If my trainer difficulty setting was 50% or half way Things get a little trickier Zwift first halves that value so -10% becomes -5% sent to the trainer then that is halved again based on my user preferences So what happens there is a -10% gradient with a 50% slider Means I only feel negative 2.5% here on the smart bike or the smart trainer But do remember in game the Avatar doesn’t know any different. He’s still flying down -10% Okay, so that’s the theory of how the training difficulty setting works both uphill and a little differently downhill Let’s put that into practice. What I’ve got here is the Kickr bike with tilt I’ve got the virtual tilt shown on screen and below that the physical tilt the bike is being sent by Zwift So as we go up the climb here with a maximum slider set 6% 7% Very close to it. So one for one uphill with the trainer difficulty setting to maximum or 100% So nine. Yep, very close drops down a bit Things get steeper around the corner here 11% . There we go And you can see that almost one for one with virtual reality and the real reality here on the Kickr bike So on the descent what we should see is half of what we have on screen there simulated, let’s check it out Okay, -7%. Bike -3.5% There we go confirmation on that one that Zwift halves the negative gradient when the maximum trailer difficulty is on There we go -3.5% , -3.6% and down to the flat so there we are confirmation of the theory and How things work with Maxium trainer difficulty enabled. Let’s go set that to half and see how it goes up and quarter down Okay settings Trainer Difficulty slider You know, it’s not a perfect science, but I think that’s close enough. Okay back to the ride Exactly the same test as before with the same information on screen The Zwift figure being and what the avatar has to deal with (that doesn’t change) and the figure below that is the Kickr bike Which is what’s being sent to the trainer or smart bike. Zero zero looking good Okay up we go 6% Just over 3%, 7%, 3.5%. There we go. It’s half the figure set for the trainer Remembering the avatar still has to ride up that steep gradient. Nothing changes there 10% 5.5%. Yep And the turnaround remembering Zwift will halve the gradient by default and then halve it based on my preference So I’ll turn around and the simulated descent sent to the trainer There we go that -2% Again avatar doesn’t change My riders still flying down that descent but we have One quarter of the descent simulation with a trainer slider set to half So there we are is the title of the video stated the trainer difficulty slider There’s something more you need to know about the descents now This has been confirmed with Zwift and we did confirm it there with what we’re seeing through to the Kickr bike and it’s the same For any other smart trainer. I believe this decision was made early on in Zwift’s development process to halve the negative gradients That’s because on a big long descent. There’s nothing to push against and your avatar gain speed is all about generating lots There’s also a lot of differences between how trainers deal with zero resistance sent to them Some will let go of resistance altogether, some will still apply a little bit of resistance. So it kind of levels the playing field there. Could this be implemented any better way on Zwift for descents? Maybe. I think descending and descending in a bunch could be based more on your positioning, maybe a bike handling if we had some steering When it’s based on watts we need something to push against to determine who goes fast and who goes not as fast. Alrighty wrapping this one up for today. Hopefully this has been informative and interesting If so, remember give it a thumbs up and hit subscribe to support this channel. Thanks for watching

95 thoughts on “Zwift Trainer Difficulty: There’s one more thing to know….descents!

  • Finally, an explanation that actually explains this! Even the CEO of Zwift couldn't manage to clearly explain this feature on his recent podcast appearance. My question now is, does setting trainer difficulty to 0% give you an advantage on the downhills in racing, because you can push more watts on descents than people with their difficulty set to 100% (who have less resistance to push against)? Or am I still missing something..

  • So purely from a "feel" perspective are you better putting the setting at 100%, with the theory that riding fully simulated gradients will transfer to the real world better.

    OR, is having the setting at 50% just like having a bigger cassette-allowing you to spin when in real life you maybe grinding-thereby not transferring those climbing KM's to the real world.

    Also the max gradient on my trainer will be a limiting factor

    hmmm.

  • So if i am at 100% trainer difficulty are my legs not a lot more tired after climbing at a 10% gradient for 5 minutes than someone who's legs feel like they are climbing only at 5%? No matter how fast the guy on the screen is going, my legs are now 50% more tired than the other guy for the remainder of the race, no?

  • On a power based smart trainer the only real thing the slider changes is how much you shift.. If you can only put out 300w max on a climb constant, the slider doesn't change that. What it does change is how many gears you have to go through to get to the gearing that is in the sweet spot for your effort/ wattage.. At 50% slider you may only have to drop 3 gears for a steep climb where as 100% you may need to drop 5-6 gears compared to on the flats..as Lama keeps saying .. the onscreen experience doesn't change only the FEEL on the trainer.. so if you put out 300w set at 50% , Its still going to do the same things as 300 watts at 100%..

  • Sounds like that Kickr bike is making some highish pitched whining when things get real steep. That just me hearing things or is that the trainer?

  • If you do Zwift racing, a 0% difficulty allows you to stay in your big chainring for most of the races. The main reason alot of people do it. As for the trainer warrior comments I guess you would have to ask the guy who won Paris Roubaix after exclusive Zwift training.

  • About the uphill: Saw your other video on this but I'm still not getting it. So..let's say I'm training for an actual ride up Alp d' huez and using Alp d Zwift as my proxy. If I don't want to be stunned when I finally do the real climb, do I need to train with the slider all the way to the right? In other words, I want to train for an 8% gradient but with the slider set in the middle am I actually training for a 4% gradient? Thanks

  • I would never climb alpe d'Huez with a 39/25 and have no need to have a compact irl so set mine
    At about 60%
    Would an idea not be able to input your bikes gear irl and what you want to ride in game then Zwift calculates an effective %?

  • Clear as crystal, cheers Shane!
    Buuuuuut, I’m sure this must have been brought up before… riding with higher or full difficulty will be more “difficult” by the simple fact that you need to shift more (In my limited experience)
    Another thing I noticed regarding descents, after I foolishly joined a race, racing up a steep hill cresting over to a steep descent it was impossible to keep the power up going down at full difficulty and keep up with the bunch even with my fastest gear. Of course being on 1x is my own damn fault but I would still need to sprint like a maniac compared to a fellow racing on 10% sitting in the middle of the cassette the whole race.

    Not complaining though… just an observation, having a lot of fun with this, especially at max trainer difficulty.

    Looking forward to all your little zwift tip videos now🙏

  • This issue first seems like a mind-bender but hopefully it isn't … my take on it is that setting "Difficulty" is equivalent to changing gear. In-game, it still takes the same energy to climb a hill – and higher gear/lower cadence = lower gear/higher cadence = same Watts. Setting 100% difficulty just means you will need to select a lower gear for the same energy output, and same energy output therefore means no difference in-game.

  • I'm not sure I buy that 100% trainer difficulty equates realistically to real-world gradient. For example, riding outdoors I can spin up a 10% gradient reasonably well at 70-80rpm with a gear or two to spare if i'm on a good day. On zwift (same bike, same gearing) I run out of gears and end up grinding at 50-60rpm. The first time I rode Alpe Du Zwift I thought something must be broken because it was so ridiculously hard from the word go. Maybe it's psychological and i'd love a power meter on my bike to compare indoors and outdoors properly.

  • Wonderful if Zwift adds shortcut for difficulty on screen or companion, easier for manipulating the ride instead of 3 , 4 steps to adjust it

  • For me it's all about opening up more hilly courses for my riding enjoyment, without completely blowing myself up, or overstressing my knees. My approach is to decide what I want my minimum cadence to be going up a long hill (for me 70-75rpm). Then what is the lowest gear I want to have to shift into on the bike to maintain that cadence for at least 20 minutes. Set difficulty accordingly.

  • I don't put it on 100% because when I'm descending and going about 65-80 km/h in game I am riding 53-14 irl. Then when the gradient rises in game (i.e. the Epic KOM descent) my trainer resistance increases based on the in game gradient, and I have to shift to 39-23 super fast (which would mean 20 km/h @90 rpm) for me to keep a comfortable cadence, while my character is still doing 40+ km/h. This could just be me exaggerating, or they should add some adjustment for momentum in the game.

  • On some trainers that attach to the wheel they are a lot more fluid at higher wheel speeds. If I am pushing op 11% at 300w at 7mph my trainer really doesn't like it. At 50% it allows more speed at the wheel for the same power which is in a better place for the trainer to handle as its rotational speed is higher. Also it is sharing the loaded force over more tyre rubber so is less harsh on tyre wear etc.

  • Is the difficulty setting if you're doing a predetermined training session different to this? (up and down arrows in the companion app if you are doing a training ride). Thanks for the video as usual!

  • Sick vid Llama! Wish my content could be as awesome as yours 😀 Keep spitting out more videos, if you'll pardon the pun 😉

  • Please can you do a zwift test up a reasonably long climb with the trainer difficultly set at zero, medium and high and measure your avg heart rate for the 3 efforts. Fairly convinced it will change for each effort depending on your riding style preference. I appreciate the times will all be the same. The steeper and longer the climb i believe the better the results will be.

  • I know you covered this in an early video but I just wanted to confirm. The default difficulty slider setting is somewhere around 50% so it’s only sending half the resistance to the trainer. Got that part. It’s my belief that the avatars progress is strictly watts based, in other words, it may feel like half as much….but the avatars speed during the climb is that of x watts at the actual grade/rider weight so the avatar is moving slower that you’d expect with a halved resistance. God, this is the worst worded question ever. Sorry 😐

  • Trainer Difficulty is a conspiracy, it was added to cause internet arguments and controversy to help market the game 😀

  • I'm not sure if my understanding is correct… If you compare the setting at 50% and 100% does this mean that for the same uphill distance in Zwift it will take you twice as long to get up?? I assume that if you are going up a hill with constant gradient and that 300W will get you up in 10 minutes that as long as you are deliverinh 300W it will take as much time (and feel the same) whether you set the trainer difficulty to 50% or 100%. My understanding with regards to "feel" is the amount of Watts required to push you forward. In any of the settings it should always be the same.

  • But why? Why is the default trainer difficulty in Zwift 0.5 (which entails 0.5 uphill and 0.25 downhill)? What's the benefit; does the ride feel more realistic or what's the reason?

  • If you have time, can you speak to the lag time between elevation change on Zwift and the adjustment to the trainer? Why? I do not have a smart trainer and for the most part I'm happy going sans smarty trainer (watts are watts … right?) But when I race, I find myself constantly looking up in the right hand corner at the gradient. Basically, I want to avoid situations in which I'm putting out 400 watts while the guy next to me is putting out 0 watts because he/she knows we happen to be on a descent. And most of the time on most Zwift courses gauging when I'm on a descent isn't really much of an issue. It ain't an issue on long descents and on "choppy little rollers" — think those small rollers on Watopia or the Crit. But Yorkshire and New York just cause me fits in parts because you come across these short and sharp descents so often! Of course I should just get to know these courses better, but would a smart trainer help? My theory is that if I could just feel the change, I would immediately know when to lay off. Sipping every ounce of energy is important!

  • How does this affect the hack of amending the wheelbase figure in the Wahoo app to give you true gradient feel on the Wahoo Climb?

  • I know that trainer difficulty doesn't affect climbing time assuming you are putting out the same wattage. However does it make it easier to set a fast time on zero difficulty as you can just stick to a constant effort rather than the fluctuations that occur with changing gradient and gears? I'm thinking here of the longer 20min climbs that have flatter sections. I always keep the difficulty at 100% as I find it makes things more interesting but I've often wondered if 0% would be better if I was trying to get a fast time!

  • I'm sure it varies a lot on preference, but I saw somewhere that most Zwift racers set the difficulty between 20% and 40% to get the a balance of having a little more resistance on hills to push against, while still being able to put power down over the top of and down hills as well. I've found that with it set too low I lose position on short, punchy hills like on Richmond where others can keep it in the same gear and let the "bite" of the resistance change surge their power whereas I have to shift up even on a climb to do the same thing. I'm at roughly 30% now and find it the best balance for me. I don't understand turning it all the way down and making even the Alpe a flat TT, but I guess if you're training for a flat TT…

  • I’m more confused now than I was. So if I’m riding up epic kom at 90rpm doing 250w what’s the difference to me between say 50 and 100%?

    Is it just I’m in a different gear physically on the bike?

    I’ve just always had it set about 75%.

  • This just confused things. When I look at your power & speed, they seem to stay the same while climbing (I didn't look at descending) regardless of what your Kickr says. If your power and speed stay the same how can the gradient change? Or are you saying that the power and / or speed displayed on the screen is wrong? So at full slider the power is right but at half slider the power shown is really twice my actual? But, that doesn't make any sense because I run with a separate power meter and my power is always the same between my Computrainer (Zwift display) and my Stages (watch display).

    But, now that you bring it up, my distance can vary a fair amount, especially on a hilly course. I have a Garmin "speed detector" (counts wheel revolutions) and I'm assuming that the Computrainer sends its "figured out" speed to Zwift as Zwift does have speed when hooked up to the CT. However, in coast mode, the Zwift speed will be higher than the speed on my watch (from the Garmin sensor). I'll have to look at this much closer over the next while.

    In any case, what you are saying disagrees with what others have posted. Others have stated that the slider just gives you lower (or higher) gearing so that if you are running a corncob on the back, you move the slider to the left to simulate a 28 or similar on the rear. You are saying that moving the slider to the left simply makes it easier and decreases the grade so that you don't have to put out as many watts to climb the hill – or, does Zwift say you are going slower than you actually are so you put out the same total watts?

    Still Confused. Well, now, more confused.

  • Don't quite get this your first ride the slider was set to max, on climb at 7% sign , data was 78 rpm 298 watts 16 kpm — second ride slider set to half/ at 7% sign, data was 73 rpm 361 watts 18 kph which means the avatar was climbing faster as it works on watts to climb % value for speed so you must have been on smaller cog second ride so there could be an advantage to be had with slider set lower than max and if you the rider can also spin fast as well to my mind there is an advantage. Watts can be produced by spinning fast to get say 200 w like Chris Froome does it or by going on a smaller cog and spin slower to get the 200w which is more stress on your legs so if you can spin fast it's less stress than pushing force through the pedals for the muscles. Just a thought 👍

  • Go to Zwift Rider Facebook page. See one of the 23482348 posts about the slider.
    Go to this video link
    Control C
    Control V

    Still seems weird to use the word "difficulty" rather than something else. Sure at this point it has become a meme on that group. But I'm sure there are plenty of people that truly do think you directly go faster/slower based on that slider. Also strange that they halve it going down. I mean I get it but it seems they could just have 2 separate sliders. One for up, one for down. And the default set to 100% for up and 50% for down.

    I'd probably set mine to about 90% up most of the time (simply due to using wheel on trainer and my trainer wheel has a an 11/28 cassette while my outdoor has an 11/32) and would probably set down to like 20% (so I could feel some change just for immersion but I'd honestly rather just keep pedaling)

    Or in group rides (to avoid surging) I'd set around 25% up and 0% down.

  • Ok my take on this is the following. 1) 250w up a climb equals a given speed for your Avatar. You still have to produce 250w regardless of your cadence and what gear you use….but 2) the difficulty slider allows people to make full use of their gear ratios depending on their ability. If you build a trainer capable of handling 500w in a high gear, but a user can only hold 150w, then that Smart trainer would be 'too hard' for them, and they would spend whole time in bottom few cogs. The slider allows for the differences in smart trainer ranges, AND the differences in user's capability. It does not make pushing a wattage in game easier

  • so to get down ADZ fast it would be best to put the trainer difficulty to near zero to be able to still make power ( and have gears still) as apposed to 50 or 100%. hmmm new things to try out 🙂

  • During zwift races it's much easier to maintain watts on decent with trainer set to zero. It's a good idea for Zwift to make that setting fixed for races.

  • Interesting. For me cadence on a known gradient outdoors is only replicated indoors when I set the slider to 87%. Are Zwift's gradients the same as outdoors? At 100% I have to shift up 1-2 cogs larger on the trainer otherwise I end up grinding.

  • This is a concept I understood early on that seems to fool many Zwift riders. I do believe there is one big difference though that does not get talked about too often and that is flywheel inertia. If you are set to 0% difficulty you can climb a 12% grade in what would be a flat road gear, big chain ring. That gear will spin the flywheel faster and therefore give it more inertia. You still do the same amount of watts sure but one is done with low inertia (100% difficulty) and one is done with high inertia (0%). Maybe it is all in my head but high inertia on the trainer always seems easier than low inertia for the same exact power output. Not sure I know how to explain that though…

  • I have erg mode workouts I start mid ride and tab to finish when you get stuck on a long downhill so I don't waste time sitting around.

  • it should working with flat also, because i have MTB XC bike, where cassete 10-50t and one star on front 38t. I'm constantly on small stars and arrange all workouts in the mountains. Only ERG mode saves me with Tacx neo 2t…

  • Shane, this is the best explanation of the difficulty setting that I've heard/seen yet. Unfortunately, no good deed goes unpunished. Pandora's box has been opened. At least you'll get the views!

  • The only control that Zwift has to control the trainer resistance is the virtual elevation.

    The trick in all this is that the wheel speed on your bike is not the same as the wheel speed for your in-game bike. Changing the resistance changes the effective wheel speed for your real bike based on the watts you are putting out. Lower resistance allows higher wheel speed, higher resistance means lower wheel speed. This translates through your gearing to set the cadence your legs see.

    In practice, just like with a car, you want to match your torque curve at specific RPM's to optimize the power output. Typically you will put out (comfortably) highest watts for longest when your cadence is between about 60-100 RPM. You can do that with gearing alone or with gearing plus changing the trainer difficulty.

  • Other than some speculation, I’m still none the wiser on ‘why’ this feature is there. I’d rather there was an option to turn that (poorly named) tuning off completely, for both up and downhill.

  • Trainer difficulty Zero Gang Represent! Was tired of having to shift down 17 gears (With the power loss associated with a gear change) while cresting a hill in a zwift race. WHile everyone else riding at Zero difficulty gets to apply constant power.

  • Hi shane we need a test about when makes it sense in race changing bike in jungle and when not, people are so confused and different opinions about this 😂

  • What I'm trying to workout is what is the best difficulty setting for racing – specifically for not getting dropped at unexpected times. It seems that at 100% you may have sharper spikes in resistance when the gradient changes suddenly (and have to change more gears) but this will likely result in you spiking your power which in turn will help you keep up with the pack. A lower difficulty setting would not result in the spike in resistance and you might not notice until it's too late and get dropped and have to work hard to get back on. I've been using 50% but I think I'm going to try 100% now. Thoughts?

  • The way I have always looked at it Shane. The slider just changes your cluster (virtually of course). 100% is an 11-21. 50% is a 12-28 etc etc. I understand it isnt quite as simple, but it seems a fair way to explain it.

  • Shane, riding my smart rollers I am very happy Zwift does this, otherwise I would not be able to ride down hills as I need resistance to keep pedalling and stay upright.

  • This is not the complete picture. When the slider is reduced, the speed of the rider reduces too for a given effort. It’s not as easy as putting the slider on minimum and flying up the hills. It’s equivalent to altering the gearing.

  • Don't really know why Zwift have an option to go less than 100% difficulty. Surely the majority of users are using smart trainers to improve performance out there in the real world where such an option does not exist.

  • Forget the trainer difficulty, I didn’t realise “ride on’s” collected in your back pockets!! #needmorefriends 😂

  • It would make more sense to double the gradient on descent when difficult is on half than to reduce it. I always stay on max. Why not just send the same value to the trainer as what is displayed? The point is to simulate reality as close as possible. I hope zwift will make this an option. Still the best online simulation and the power based training is incredible.

  • I'm set on 50% and I was always wondering why I've never dropped to the small ring on my climbs. When I got outdoors and hit anything above 6%, I hit the front derailleur and roll on my 36. 11-28. Well I'll try 100 % and see what happens

  • I don’t understand why the option even exists, on the road you can’t adjust gradients…nor feel or whatever. And it still an outside sport right ? Cycling ? I’ll keep mine on 100 and push more when needed, which is the purpose of it

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