“Trainer Difficulty” is absolutely the most misunderstood Zwift setting (Menu>Settings). Zwift’s help video says:
This adjustment won’t change how far or fast you ride, but it will change how climbs feel…
This setting is really a “gradient scale.” Zwift is constantly sending current gradient numbers to your smart trainer, and the trainer adjusts its resistance to match the gradient you are riding. The Trainer Difficulty setting scales the gradients sent to your trainer.
Trainer Difficulty is set to 50% by default, which is why Zwift says it “treats the gradient as half of the true grade.” So when you hit a 10% climb in Zwift, your trainer is only giving you the resistance of a 5% climb.
Bump your Trainer Difficulty up to 100% and you’ll feel the full gradient. Set it to 0% and you won’t feel gradient changes at all!
How Trainer Difficulty Affects Your Ride
Lowering your Trainer Difficulty decreases resistance changes on hills. You still have to put in the same amount of power to get up (and down) the hill, but you will “feel” the hill less.
Another way to look at it: Trainer Difficulty determines how much shifting you will need to do. Where you might typically use ~7 of your gears when riding at the default 50% setting, lowering it to 25% would let you ride and only use ~4 gears, since the incline changes are less dramatic.
Increasing your trainer difficulty, on the other hand, will force you to use more gears. So instead of 7, you may use 10 or 12, since the hills will feel steeper and you will need to shift more to maintain a healthy cadence.
What It Does Not Do
Changing Trainer Difficulty does not change the power needed to get up the hill. You still have to put out the same watts to move the same distance as before… you’ll just be doing it in a different gear.
“Trainer Difficulty” really is a misleading name for the setting. Perhaps “Gradient Feel” or “Trainer Realism” would be better.
Frequently Asked Questions
Doesn’t a higher Trainer Difficulty make racing harder? Am I “difficulty doping” by running it lower?
A higher Trainer Difficulty will typically result in a higher VI due to more resistance fluctuation. For many riders this may result in an overall effort which feels more difficult since maintaining steady power is easier than doing intervals.
But this isn’t true for everyone, and skilled shifting can reduce or eliminate the effect of resistance fluctuations.
In the end, watts are watts, and your Trainer Difficulty setting doesn’t change the power needed to cover any particular stretch of Zwift tarmac. So set it wherever you’d like!
I’m spinning out on descents. Can Trainer Difficulty help me here?
One common complaint from smart trainer owners is that they get dropped by other riders on downhills. Especially if you’re running Trainer Difficulty at 75% or more, steep gradients simply won’t offer the resistance needed to put power into the pedals. It’s the same outside!
The problem comes when you’re racing against others who have their Trainer Difficulty set low, or perhaps are riding dumb trainers with a constant resistance. These riders will have the resistance needed to go hard on the descents, while you’re spinning out.
Trainer Difficulty can help here. Try lowering it to 25-40% when racing. This will make hills seem less steep, and allow you to put more power into the downhills. Give it a try and tweak the setting until it feels good to you.
For more on this topic, read Trainer Difficulty On Descents: Did You Know? and Hanging with the Group Over Gradient Changes. Also–don’t forget the Supertuck!
I have a KICKR Climb, but it doesn’t respond to gradients because I’ve lowered my Trainer Difficulty. Is there a workaround?
There’s a pretty simple hack for this–see KICKR Climb Wheelsbase Hack for details.
Why don’t I see “Trainer Difficulty” in my settings?
The slider is only visible once you’ve paired a smart trainer as a “controllable trainer” in the pairing screen.
Should I Change My Trainer Difficulty Setting?
No need to change the setting if you are happy with the “feel” of your rides and aren’t struggling with yo-yoing in and out of the pack on group rides. If you think you’d like to adjust it, though, go ahead and give it a try–you can always set it back to 50%.
Thanks Eric for this article.
It helped clarify what this setting does. I was training at 50% (the default I think) and last spring, when I went outside to real hills, some of them kicked me pretty good. So I want to up the trainer feel of the hills for climbing so that when I go outside, there isn’t as big a difference.
Thanks – I am bumping up the setting to see if it helps with this.
I have the Kickr Core. Why don’t I feel the cobblestones, dirt, or wooden planks when I ride Zwift? Is there a setting I’m missing somewhere? I have already paired with bluetooth and the Controllable trainer.
The KICKR Core doesn’t have a road feel feature. That’s just the Tacx NEO trainer.
I don’t like the TD-setting at all, to me there shouldn’t be any other option than 100 %. What’s the point and sensation in going up the Alpe du Zwift without feeling its true gradient? When I started Zwifting about two years ago I didn’t have a clue about TD and it took me a while before I became aware of it. Now I always use 100 % because it’s so much more real, and fun, and anything else feels rubbish to me. Everybody is of course free to use which setting they like but I think there are a… Read more »
When climbing the Alpe Du Zwift with the setting at 100% you must shift into a gear that is the right resistance for YOU. Say hypothetically for you that is 75 rpm at 250 watts. If you lower setting to 25% you will STILL have to change gears to get to 75 rpm at 250 watts. It WILL be a harder gear and the rear wheel will be spinning faster but the game will move you the same amount for every single watt and it WILL FEEL THE SAME to your legs. The ONLY TIME it becomes an issue is… Read more »
Sorry but this is just a harmful comment. Many of us depend on the trainer difficulty to enjoy Zwift. I don’t have the gearing on my Wattbike to get up Alpe du Zwift on 100% trainer difficulty, so are you suggesting I don’t bother? This setting is not mandatory you shouldn’t mock something just because it doesn’t suit you.
I always ride with setting at 100%. Personally I like the regular shifting. It turns what can be a rather monotonous task into one where you’re constantly having to pay attention to what’s happening (I use for general fitness over winter rather than training for races). With trainers in the past I’ve required music, etc., to overcome the boredom. I now usually ride 1.5 hours with nothing other than the zwift screen in front of me. The necessity to be on the ball keeps it interesting and the miles fly by.
This article really helps clarify what the slider is used for. Up until this point I thought that it was increasing or decreasing the resistance across the board. Does anyone know if this is available elsewhere? The issue I’m having is that my mountain bikes gearing is not great for riding many areas in Zwift. Even with the slider at 100% I find myself operating in the highest two gears 80% of the time. I believe that a way to increase overall resistance or a virtual shifting feature would help out a lot of riders who are not using road… Read more »
I wish this feature existed in Zwift, but it does not! Depending on your trainer, there may be ways to hack it from the trainer’s side, via the app used to set it up. Might contact trainer support.
Just increase your weight in the game
I have been using Zwift for 2 days.
I use Elite turbo muin smart b+ indoor trainer.
I can’t see the trainer difficulty setting in the settings menu. Why is it?
I use Zwift on my computer(Windows10) and on my Ipad.
I am still using the trial version.
Make sure you have your trainer paired in the “Controllable Trainer” box on the pairing screen.
Unfortunately I can’t pair my trainer in the controllable trainer box. 😞
My trainer only transmits power.
Csabi, and that is why you can’t find the slider. It affects the feedback. Yours doen’t have feedback from the programme to your trainer at all, so adjusting it isn’t an option.
Hello Eric, in the app of my iPad does not appear this function, why? Thank you
forget it now i see it sorry
Thanks for writing this up! I have a gravel bike SRAM 1×11, typically using the top 3-4 gears only, and can spin out on the descents. If I’m understanding this correctly, if I increase the TD setting to 100%, I will probably use more of my lower gears to climb. However I will probably still spin out on descents, unless my bike had higher gears. Does that sound correct?
This may be a minor point, but does Zwift send gradients to the smart trainer, or does it send the required brake force (or maybe brake torque) based on all of grade, wind resistance and rolling resistance, the latter two being calculated by Zwift based upon the riders speed. Or maybe it sends both so the Kickr Climb can do it’s thing?
It sends gradient, rider+bike weight, wind resistance, and rolling resistance… maybe more?
It’s up to the trainer’s code to simulate the feel properly based on those parameters. (The parameters may vary a bit between Bluetooth and ANT+, because it’s two different protocols and specifications…)
That interesting (and surprising). Since all of those factors ultimately result in that single number (brake torque), it would allow for simpler design of trainers and for Zwift and its competitors to bring in sorts of different factors that they might imagine to make the experience more like IRL. For example, I think if Zwift could just transmit the brake torque it would be easy to implement draft feel.
The separate values could improve simulation, e.g. having the trainer physically incline or adjusting fan speed to simulate the wind.
Thanks for explaining how TD settings impact on the experience. One thing I’m finding out reading your post is that one has to shift through a climb… I’m confused as I thought that ERG mode was taking shifting out of the equation on rides. The times I’ve tried shifting gears made a slight difference for a few seconds, but after that, no notable difference from cycling in the previous gear.
You don’t need to shift in ERG mode. You DO need to shift in SIM mode (which is what is used outside of workouts on Zwift).
thanks eric, didn’t know this! does Zwift shift you automatically to SIM mode on regular rides?
Yes. SIM mode is basically what’s used as default. ERG is only for workouts.
HI Eric, I am new to Zwift and this comment is exactly what I have been searching looking for. I have been receiving mixed messages about exactly this. So in workouts (training- FTP tests,and plans, etc..) I do not need to shift- Zwift will automatically take care of that..,…however in Routes in Watopia, etc..I do need to shift my gears?
Thank you! I’ve been on Zwift for a few months. I’ve read tons of articles and watched hours of video, yet the basic notion that you have to SHIFT during regular rides totally escaped me! I feel like an idiot but I’m also excited to apply this knowledge on my favorite Innsbruck climb!!
My mph seems way off. I am new to Zwifting, however, not new to riding and I know what speed I am capable of riding. I tried the calibration method and it still is not close. Any suggestions? Thanks
Contact Zwift support, or your trainer support. It’s all based on the wattage your trainer/power meter is sending out. [email protected]
Is there an easier way of going into the menu, instead of starting your ride first then pausing to bring the menu button.
No need to pause. Just click the mouse or tap the screen to bring up the menu button. You can keep pedaling while in the menu…
You must be kidding. I thought everyone rode with trainer difficulty at 100% or you were cheating or certainly not preparing for the climb outside of equal difficulty. Really some riders go at 50%?? I missed that note. Got it now.
Default is 50%. I would guess the vast majority of people run it at that!
Zwift why don’t they sell a turbo trainer that sends a code to set the resistance when you click the button to start a race. Every one would be riding to the same resistance setting that would be a game changer😀
Hello! I use zwift since 2 years. I always let the setup at 50%. My ftp is 270. I go quite strong on flat TT, performing exactly what is expected with such http://ftp... But in Alpe du zwift, I cannot go beyond 220/230w continuous or I totally overheat. I thought it was because of lower pedalling speed, or anything else. But yesterday I touched the setup, put it at approx 25%. And surprisingly, today I was way faster, climbing over 250w. The feeling in climbs is much easier at previous speed, the difference is huge. This is not supposed to… Read more »
Trainer difficulty would change your watt to actual gear ratio relationship, any improvements would be due to you and/or your bike being more efficient operating withing a smaller range of gear ratio fluctuations.
N.CRX you have two groups of muscles slow and fast twitch; the amount of fast twitch muscle fibre is set at birth; climbers have plenty of fast twitch muscles, these muscles utilise different mechanisms for ATP generation (ATP is how all cells survive it is the molecule of life and responsible for energy production) ; fast twitch muscles have no mitrocondria which are the way slow twitch muscles generate ATP and energy. slow twitch are predominately used in high cadence exercises you are using oxidative mechanisms, fast twitch are engaged when the cadence drops. so going up at 100% TD… Read more »
Eric, do you know if TD could be changed during a race and if so, is it allowed? As this would /could have major consequences.
Yes, you can change it on the fly. No rules preventing it that I know of. Wouldn’t have any consequences other than how it affects you!
Thank you Eric,
That is very good to know, but you say it has no consequences?
What about recovery after a steap climb @ say 5% followed by a descend @ 100%?
IMHO it has major consequences that way
Not sure what point you’re making, Rob. I said the only consequence is how it affects you – meaning there is no consequence outside of that, like being DQ’d from a race.
There is one important piece to this that needs to be made clear. At some point, when the gradient becomes very steep you will have an insufficiently low gear to enable peddling at comfortable cadence. The gradient this happens at changes depending on trainer difficulty. Ie you may find that going up Alpe du Zwift with difficulty set to 50% is possible in your lowest gear at a reasonable 70rpm. However, set this to 100% and you cadence may drop into the 40’s! which is hard and very like real life. While it is true that pushing the same watts… Read more »
Great point, and this is what people talking about “cheating” do not understand. I have an 1x drivetrain and could not possibly go up the Radio Tower and keep a decent cadence (not even,say, 50 RPM standing). Reducing TD is the only way. In a way, reducing TD is like moving your front derailleur to a smaller chainring 😀
I think the TD wants improved or removed. It is not natural that if I want to simulate the outdoors I have to change gear 60 times per minute. In my opinion it would take a slider that regulates the speed of the changes slope and not intensity slope
Hi Eric, I can not seem to find intensity adjustment when using iPhone to drive program. I can Only see option to calibrate smart trainer. I can see ability to adjust intensity when using Apple TV (but prefer to drive program through iphone), if I adjust intensity Though Apple TV will it revert to default 50% when I close program through Apple TV? Is there a way to adjust using iphone.
thanks in advance
Help. I moved my slider to 100% as I thought it would help me on downhills. I ride a Neo. Last night in a group ride on Harrogate A friend who I outweigh by more than 10KG went flying by. I was was doing 183 watts (above my threshold). I clicked on her stats and she was doing 73 watts. What do I do to catch the draft of these speedsters? It just doesn’t happen.
What happens if you turn the trainer difficulty to the OFF position?
Then your resistance never changes. Like riding a dumb trainer.
Perhaps this setting is too complicated for me…and if so, and the reasoning below is incorrect, I’d love to get a _mathematical_ explanation for the setting. I do not understand why Zwift and others continue to say “This adjustment won’t change how far or fast you ride, but it will change how climbs feel…” There’s simple math involved here, and if at 50% it “feels” 50% easier to turn the crank than at 100, then the rider is not putting as much power to the crank. Or if the 50% rider “feels” that he’s putting the same effort to the… Read more »
The physical explanation for the trainer difficulty setting is kinematic decoupling. Bicycles in the real world have a fully kinematically coupled drivetrain in the forward going direction. Kinematics describes the physical operation of the drivetrain without consideration of any forces. One turn of the pedals results in a certain number of rotations of the rear wheel due to the kinematics of the drivetrain. Tire slip on the road surface is negligible, so forward speed of the bike is determined precisely by the pedaling cadence and by what gear you are in. The only way to change the kinematic relationship between… Read more »
Thank you! I realize now that my (obvious) mistake was thinking that when everyone said “it will ‘feel’ different but nothing will change” that “nothing” excluded _cadence_. To maintain the same power (and so speed) at a lower Trainer Difficulty, the rider will need to spin up the cadence.
What they mean is that the work needed to complete the climb remains the same. Work = Force x Distance For example, you can have two hills that both take 100Joules to complete. One is steep but short (10N x 10m). The other is less steep but longer (5N x 20m). The person who finishes the work (100Joules) the fastest is the winner. (Incidentally, power is in watts. Watts are Joules/second. So power is the rate of work.) So one hill is half as “steep” but you have to cover twice as much “distance” to do the same amount of… Read more »
So if I set TD as zero, it would be the same of enabling ERG mode? I will not need to change gears?
Not the same as enabling ERG mode. But it would just keep you at your trainer’s 0% gradient level of resistance, regardless of in-game terrain.
What is the setting “Workout Pain Effect” for?
It adds a blur to your screen as you near the end of hard intervals. Sort of a tunnel vision thing.
Is it not the case that max incline and power are good indicators of a trainer’s capacity to handle lower resistances too? I would guess an elite drivo ll is going to be happier at 9% than a flux S at the same even though both are capable? You don’t buy a car and redline it everyday if you want years of troublefree use. On top of that I’ve seen that manufacturers clarify these limits by speeds so a trainer with max 25% presumably has more flexibility for hard climbs in big rings too?
Hi Eric, i currently have a 25T easiest gear cassette 32T front, while doing the Epic KOM and Radio Finale, i was in 32/25 and barely made it up @ 50% TD i think i was at 17rpm cadence, would setting a lower TD essentially give me easier gears to spin with? should i just get a bigger cassette and call it an investment for the bigger routes to come.
Hiya, I am using Zwift and a Wattbike, I am 77Kg and FTP 215. Yesterday I had to do 2.5-3W/Kg 200-220W to stay in a group who were 1.5-2W/Kg. Why am I having to work harder? One bloke who was 6ft 2 and 215lbs av. 190W….please help!
So as of July 2020 a hack is the only way to get the KICKR Climb to work accurately with Zwift???
Great article; your site is awesome. I was riding with the difficulty set in the middle but then maxed it out because I was interested in “Veresting”. What I’ve noticed: when you hit a climb, even just 2% grade, the resistance increases dramatically. That said, it doesn’t seem to increase much more as the grade increases. It’s sort of like it hits hard when there is a climb of any sort but it doesn’t really matter how steep it is On descents, though, it’s amazing. You pick up speed really rapidly It would be sweet if there was a way… Read more »
I have a wahoo kickr and no matter how fast I pedal, my trainer will not go over 12/13 mph on straights and 13/14 mph going downhill. How can I fix this issue? Please don’t say pedal faster!!!🤣🤣
a few ideas…
1) make sure you have it paired as a controllable trainer
2) make sure it isn’t paired with another device that could be interfering with setting resistance
3) do an advanced spindown calibration: https://zwiftinsider.com/kickr-factory-spindown/
4) contact Wahoo support (it may just be broken)
5) pedal faster! 😄
I don’t know if this is an appropriate place to ask this; but I don’t have a “smart trainer”, is there a way I can follow along on my old trainer & just approximate by using my resistance levels. Just want to try this out to see what it’s all about?
Sure you can. Here’s a post to help you get started on Zwift with a classic trainer: https://zwiftinsider.com/getting-started-classic-trainer/
I just recently got the Kickr Snap smart trainer…I bumped my trainer difficulty to 100% and when i am doing a training session in ERG mode I feel absolutely NO inclines or declines. It is as if I am at 0% the entire time. What am I missing here? In sufferfest I can feel the resistance in workouts, but not zwift…I really like zwift but I can’t figure this out. Any suggestions? Does resistance only work with certain workouts?
In ERG mode you don’t feel inclines or declines. Rather, it changes resistance to force you to hold a particular wattage.
I’ve got mine set to 80% hurts my knees on 100% some says it cheating , i disagree as I personally find this allows more gear choice.
Can I please ask how I get released from the naughty step.. back in 2019 I started riding then Zwift entered my life…. I had an account but used to use the Wattbike in my local gym. The trainers that I used couldn’t have been set properly. In the last month or so I have signed up to ZwiftPower to race online with my bike club. I hadn’t realised being a newbie that I have unknowingly been riding out of Category… didn’t understand the jargon… I had no clue what a FTP let alone what watts were !!!!! I have… Read more »
How does this effect sprinting? I hit much better powers on Sufferfest on anything form 1 to 30sec. Zwift seems to just top out (looking at power graph on bottom of screen. Sprinting in 52/13 cadence shoot up, ie. resistance is low
It doesn’t affect sprinting on flat ground, but it would certainly affect it on inclines or declines.
New to Zwift so getting caught up on all the settings and features. If I understand correctly, it appears trainer difficulty alters the elevation profile that the rider experiences. Set to 100% the rider feels the change in resistance simulated by the actual elevation profile shown on the screen. Lowering the trainer difficulty flattens the elevation profile resulting less varied resistance.
How come I’m not able to adjust Trainer difficulty when I´m using AppleTv or iPad?
Are you on an Elite trainer? Mine seems to keep going back to 50% (instantly) as well on the Elite, but the Wahoo doesn’t…
Interested on how this Trainer Difficulty setting compares semantically to Erg-Mode. Seems like finding similarities between these two technological circumstances would aid in the understanding of how TD effects the rider vs how it effects the “ride”
I was originally going to say that there’s no useful comparison, but actually…
Power = Force x Velocity
ERG holds Power constant. It adjusts Force in response to changes in Velocity (pedal velocity, cadence).
Work = Force X Distance
Trainer difficulty holds Work constant. It adjusts Distance in response to changes in Force (specifically, one variable of the Force calculation: grade).
I was watching a YouTuber “Everything is Photogenic” and from her critique of Trainer Difficulty I feel confident in referring to the setting as VIR “Variable Inertial Realism” 😉
Haha. Well, at that point, you might as well call it “Trainer Difficulty”.
To be serious, I think yours a good description with respect to Zwift races.
When it comes to the ways non-Zwift-racers use Zwift, it hardly matters. Functionally, it’s more like a cassette change. It doesn’t map 1:1, but with so many other fudge factors, the discrepancy is lost in the noise.
Ahh! I was just sent here by Zwift support as I find the ride feel doesn’t seem realistic, and was concerned about how it can be fixed. I see it has nothing to do with realism – or being a “simulator”, but is in fact is a game with a whole bunch of algorithms. Why is that so hard for me to grasp? I have been comparing apples to oranges.
I have a concern about the precision of being able to set the TD slide bar to an EXACT value like 40% or 50% or 60%. I hold a weekly zwift meetup with some friends. One friend of mine and I have the exact same body weight in zwift, both put out the same avg power going up the 4.6 mile Lutscher KOM (we compared our data on Strava. I was 243 watts, he was 244w), yet I beat him by 2.5 minutes up that climb. 25 minutes for me, 2.5 minutes longer for him. That’s a 10% difference. We… Read more »
If I understand Eric’s article correctly, the TD won’t affect the climbing speed, if power and weight are same. Setting TD “too” low means you have to do more cadence, setting it “too” high means you have to apply more force on the pedal at lower cadence. The product of velocity x force = work Power being constant and weight set correctly, no difference would occur. I consider different setup (trainer, platform, protocol, calibration…) causing the difference. For fairness reasons, I would prefer choosing TD only functional when game is paused. In races, one can have benefit changing TD and… Read more »
I hope you can help. I have a Kickr and I do NOT have the “Difficulty Selector” visible for me to change it in order to work with Climber. Can you help?
If you don’t have the Trainer Difficulty slider in your main menu, that means you haven’t paired your KICKR as a Controllable Trainer (bottom-right on the pairing screen).
Not sure you’ll see this as it’s an old article but last night I had a really tough session, put it down to tired legs, then changed the user so my wife could ride. She complained about it being really hard, even on slight climbs, and when I checked the difficulty, it was on Max.
Neither of us go in to settings and the level is normally set at default 50%.
Is there a keyboard shortcut that I may have hit to change the difficulty accidentally?
Hi Eric, if one adjusts TD, should you recalibrate your trainer?
I;m using a elite direto bike trainer and set the difficulty up to 100% but I don’t feel nothing.
What did I do wrong?
Although stated below, how to open up the trainer difficulty option is not clear at all for us Zwift beginners. I paired my smart trainer (Saris H3) as a power meter only and the “trainer difficulty” option did not appear as an option on the settings screen. Pairing my smart trainer as BOTH a power source AND controllable trainer brought up the trainer difficulty slide bar!
Hi. I cant se workout pain effect unless do a workout and regardless if I choose on in settings. I’m using the app with my Android Phone. Can you help me?
This doesn’t seem quite right. Surely to put out the same power with a lower TD then you need to have a higher cadence?
Where this is particularly relevant is on steep hills. At a high TD, you are forced to lower cadence (as you would on a real hill) because your gears and power max out. Being able to coast up a hill at a high cadence with the benefits that brings (eg momentum) means those on a lower TD are “doping”.
Recent work out using erg mode. Avg power and Np are different. Is this related to trainer difficulty?
Not related to trainer difficulty. And average power will always differ from normalized power. Two very different metrics!
Hey Eric, Thanks for this article. It was helpful for me to figure out what this setting was actually doing. After reading your explanation and experimenting with the setting, I realized one thing was confusing me regarding your explanation. In several places you refer to “power” (which is the rate at which energy is being expended, or work per unit time) when technically you were actually referring to “work” (the product of power and time). For example, In the section “What It Does Not Do”, you state that the trainer difficulty setting “does not change the power needed to get… Read more »
hi – don’t understand how the same power is needed to get up a 10% climb at 100% trainer difficulty than the same climb at 50% over the same distance?
Because in game, the 10% climb is still a 10% climb. The only thing changing is how much resistance you’re feeling from your trainer. But you’re still riding the same climb on Zwift.
It’s like riding the climb in an easy gear vs a hard gear. Same climb, just a different cadence.