The best way I can express the setting is: If the same power is put out at 0% and 100% you will cover the same segment in the same time BUT the gears you use will be different. The slider is a virtual cassette IMO...

Watching you hold 350 and not having any difficulty breathing reminds me of watching Beachbody instructor Shaun T talk through the insanity workouts. Excellent video and outstanding job on both of those climbs.

Pretty impressive to be talking 'seemingly easily' with a heart rate of 180! Motivational stuff

As always great video Shane and the best explanation of trainer difficulty I have seen. Much easier to understand.

I may be wrong, but it still seems like the best way to get folks to understand the slider is to equate it to swapping out the bike's (or trainer's) cassette. Without the slider, you'd be forced to swap cassettes when going, for example, between Volcano Flat and Alpe du Zwift. The slider is like a virtual cassette swap. Just as in the real world, changing a cassette doesn't change the climb's gradient but it certainly changes how you approach the climb.

I did wonder too. 🤔 Thanks for the great vid Shane.

Great demonstration and it helps me understand. Big difference which should be worth mentioning is the influence on the cadence max and min has.

Hi Shane, nice to see that you’ve made a video about something we discussed a few days ago 👍🏻👏🏻

Great stuff as always! Love yer videos!

Shane you’re a bloody legend. Simo.

Great video. That was me with the KOM 😂

i just started zwift trial on a volt so ill be checking out your vids thanks good content.

Loved the video ( and the setup). I normally run just a bit under 100%. Around 80% derefed thru a pragamatic approach of gears,cadance and enjoying a climb.

Nice video. It helped me to understand how it works. Thanks.

Every time it starts raining in zwift in one of your videos, I keep waiting for Von to run in with a squirt gun and start plastering you!!! ...immersion... nyuk! nyuk! nyuk!

An interesting test would be to do the kom based on feel and cover up the power data, and see how fast you do it on each setting.

At first, I thought that this setting was useless, but later on I found out that it is exremely helpful. I change it a lot depending on my inteded ride effort.

Having done similar tests with 100%, 0% and 50% up the Epic KOM, the real benefit that I also see for lower % is the fact you don't run out of gears on the block. Keeps the chain straighter! Reduces the little & big combo for long periods and allows better control of cadence. Leaving at 50% feels right, but for races 20% to reduce the gear changes 👍

I agree. I think of the slider as a virtual cassette change.

Hi Shane another great video.

Thanks 😊

Cadence changes ! you feel your legs in a different way, because your cadence increases when you slide the difficulty towards 0%. Also the range of available gears you can use on your bike decreases. So it's easier to spin out of the available gears you have on your bike. If you move the slider to 100% your cadence decreases because there is more resistance from the trainer. Also the range of available gears on your bike increases in this instance. So it's harder to spin out of the available gears you have on your bike. You still need to output same wattage to achieve same speed and time goals, but what varies is the cadence at which you ride.

Haha 218 it takes me like 10 minutes to get up that damn hill :-)

Nice video, thx! I fully agree that the total energy spent is independent of the trainer difficulty setting. However, in practice there are also transient effects playing a role. With trainer difficulty set at 100%, when I hit a steep section, I do not immediately change to a lighter gear but I keep pedaling at the same cadence and consequently increasing my power output for some seconds. In the same way, after finishing a steep section, I do change to a heavier gear, but there are always some seconds where my power output drops. So for me, with trainer difficulty set at 100%, I see more variation in my power output graph than with training difficulty set at 0%. This does have a negative effect on total performance. It's the reason that "normalized power" has been invented, providing a more realistic way of representing a rider's workload (so also performance) than average power. Of course, it's my own choice to do this "delayed gear shifting", but I could imagine many others do the same.

Just tried the same test and I much prefer 0%. Its much easier to keep steady power and cadence. I used to think this was kind of unsporting until I heard one of the In The Pens podcast guys saying they always race with 0%. Sweet.

I use a 23 tooth straight block on my drivo and lower the trainer difficulty to about 70 percent. This is to make it similar to a 32 cassette on steep climbs. The drivo is slow to change resistance so having a tighter ratio helps it along making gradient changes and make it less drastic on the drivo. Also this increases flywheel speed in climbing ranges. The drivo is more content to hold me back and not slip on steep sections at low cadence.

Great💪

Cool vid Shane, always wondered if there was a difference. One similar lama lab test that would be interesting would be on pedal stroke analysis using the vectors (or other pedal power meters) testing how heart rate changes with differing pedal styles but generating the same watts. So standing vs sitting vs rounded stroke vs stomping. If you get what I mean? The objective to identify pedalling efficiency. 👍🏼

I struggled with a sort of pulsing of difficulty feeling when on long steep climbs like Alpe du Zwift - every two or three revolutions it would spin out a little and then go back to what felt harder. I reached out to the trainer manufacturer for help and they advised backing the trainer difficulty. They told me "The Trainer Difficulty setting doesn't actually make the ride/workout harder or easier. What it actually does is change the amplitude of the resistance changes." I backed it off and hey presto, smother feeling all the way to the top. Lots of people call anything but 100% cheating, but actually, by spinning out a little with the trainer set to 100%, I was actually gaining a moments respite each time, so really, for me 100% was cheating.

Great work Shane - hopefully this will clear it up for some people - #hells500

It's the same time because it's the same work, however, the effort is very different, much easier to hold x watts on 1 constant resistance that to respond to changes, effort will shift with gradients and cadence/gearing will follow, that means that different muscles and energy systems will be more or less used

This is where zwift could do with a lap button.

Training this winter, thinking about doing all my rides at 100%. Want to make sure I'm ready for the on off on off efforts

Have to say, as a slightly heavier guy (84.8 kg), I like 50%. For races I’ll put it slightly lower so I’m not as shocked by grade changes, basically 40%-ish.

Nice test. Would doing it in ERG mode , via a custom workout give a more accurate timing? Not necessarily for difficulty slider, but say for working out how many watts to push to do a climb in X minutes?

"It should be a little bit easier to hold 350W through here." Yeah, lol, speak for yourself!!!

We should get a Lama army Jersey on Zwift!

So, you could almost simulate the resistance change while in "off" by going up a gear when the incline goes up, because then you need more power to maintain the cadence (getting that leg feel)

Seems like you could call it the "spin---->mash" setting.

5:09 Got eeem!

I think the rain slowed you down on the second lap. If it were dry you’d have been 10 seconds faster. LOL

So, the 'feel' as you say is that you notice the change in grade as it appears to change on the screen? Instead of NO change in 'feel' as the grade changes? I ask as I did my first Zwift session today and wondered why I couldnt feel the transition into the climbs nor the easing as I rolled over the tops of hills. Was set to 50% as standard. Also seemed like I had too much road speed for a given gearing )e.g. I had 51kmh indicated when I was in 39 / 23 and 260W. Anyhoots, I will work it out. Next is to dump the iPad (as it wobbles with the bike) and get an Apple TV or Chrome cast??

Does Zwift have a chart that shows how the percentage changes affect your relative gearing? For example, if the lowest gear on your cassette is 28, does lowering from 100% to 80% make that a virtual 30 or 32, or does 0% make it a virtual 42 cog? If I was going to lower the percentage, I would want to know what my new gearing is so I can relate it to outdoor riding.

Power

I find if the resistance is too low, like below 50%, I spin out too easy going into sprints. I prefer about 75-80%. I also will change the setting based on the race if I'm looking for a result.

Does a lower setting normalize to make flats a bit more "challenging" gearing-wise? Running into an issue where I can only generate good power on flats in my highest gears. The theory would say I can then drop the trainer difficulty setting and get more power in lower gears on flats and declines. Does that work out that way?

I’m still pretty new to Zwift. Just wondering about KOM’s with trainer difficulty settings?? I’ve just got a new Kickr 18 (love it! Your videos made the purchase way easier) and have noticed my climb times are a bit slower. (old trainer couldn’t control resistance) Does Zwift show you information on what riders were using when achieving KOM’s? What trainer and what difficulty setting etc?? Great channel GPlama

informative comparison.

lowering the difficulty pretty much makes you increase your RPM's. you have to produce the same wattage, so lowering the difficulty means upping the RPM's. your example here proved that too...you were doing 73RPMs on the first go, then 86 on the second go at the same location of the climb and producing the same wattage and virtual speed.

Would the trainer difficulty setting affect FTP test? I mean my Zwift difficulty setting is at max right now. I know it feels harder while riding, but while doing FTP test ERG mode is off, does it mean it will be much harder to reach your FTP goal or not?

Great video! But an unrelated question, would you mind helping me with your video set up to get you greenscreened and displaying your zwift within the same session? Thanks.

Lowering the setting essentially changes your gears on the bike. I live in flat country so my bike gearing isn't set up for 10%+ climbs. Lowering the setting to < 50% alleviates that issue without having to install a new drivetrain just for a virtual ride.

Shane's cadence up the hill was 79 rpm @ 100% and 86 rpm @ 0%. For me the trainer difficulty makes it easier on the knees at lower settings.

Can you only aero tuck on specific trainers or is it possible regardless of trainer? As long as it's the right percent grade and speed

Hey Shane, enjoy the channel. Just got a Kickr 18 and CLIMB and my first ride on Zwift was fun, yet I found myself in a range of gears that I normally wouldn't expect. I was spending A LOT of time in 52/13-17 whereas I normally wouldn't be able to handle it. In theory, if I increase the difficulty slider in Zwift this would effectively put me back into a more RL range of gears, correct? I didn't touch my small chainring on my first ride in London. I also performed a spindown after 10 minutes of riding as recommended. Thanks!

So with that slider to zero it would be like cycling on a non interactive smart trainer, like for example the Elite Turbo Muin. Is that right?

When going downhill with the difficulty set easier the flywheel never backs off on your tire, so you don't get much of a break in the legs going down hill, in a real life scenario you're probably going to be taking your legs off the pedals sometimes especially in a draft, today I lowered the difficulty almost to zero for a race and pedaling the whole time really burnt the sugar up good for the whole 28 minutes. Setting it lower is ok for TT flat type of courses but for hilly/descents it's not the greatest. You just need to find the sweetspot for your gear ratio, I have a 9speed with a Tacx Vortex and it changes gradients too fast, so I like to keep it around 20%. Even at 50% the gradient changes aren't gradual.

I go 100% for races. Climbs are where the attacks generally happen and you want the trainer to give you that feedback rather than having to shift gears to put out more power. If you ride at 0% diff and don't shift on the grades the pack will fly right past you.

So I conducted a similar test today as I’m still somewhat skeptical. Been on Zwift for over two years and every single ride has been at 100% with flat Florida roads 53/39 & 11/28 gearing. The alp is a grind and best time is 69 minutes. My power would decrease as the climb progressed. Today I did it with the slider moved to about 75% to simulate the feel of an 11/32. I beat my time by 2 minutes and kept my power up almost until the end. This on the back of 25 laps of the volcano circuit the day before. So with less than fresh legs I still best my best time. I guess my hang up is if it feels easier in the legs I should be able to put more power down which increases my speed.

Good vid! Yeah ‘Watts is Watts’ and Zwift bases it’s calculations on Watts (x weight). Be aware though that higher trainer resistance / higher gear at lower cadence (for same Watts) has a different physiological impact than lower resistance/lower gear. The body will fatigue quicker (Watts will drop) with higher resistance. Arguably 🙂

My understanding is that trainer difficulty can adjust how you produce those watts ( torque x cadence). 100% you need more torque and less cadence (check video, watts and speed are the same but the mean rpm are like 70-80 on 100% and 80-90 on 0%), at 0% you need more cadence. Time, speed and wattage will be the same. This can affect your gearing but that is how I understand it. Even his heart rate was aprox. the same. I started using Zwift (and a trainer) like 2 weeks/1month, I ride at the default 50%, being a heavy rider I use more power on the legs rather than rpm. I notice that my gears always run out, I tend to use the heavier gears (big ring in the front, smallers at the back). I will try to adjust the trainer difficulty so I can take more advantage of my gears Correct me if I’m wrong, I’m new to this and only searched this now. If my trainer only makes 6% incline, am I riding on a discount everytime Zwift goes above 6%?

I equate the Zwift trainer difficulty settings as 'gears'. At 100%, I'm riding bike with a 53/39 chainring and 11-25 cogs, versus a 52/36 chainrings & 11-32 cogs at 50%. Its really only noticeable on climbs (and descents)

Would be good to explain the reverse impact on descents and how racers use lower settings so the don’t get so much free wheel effect and can generate more watts downhill

It doesn't make a difference with a huge asterisk that supposes you'll be able to turn the cranks at a reasonable cadence. This is crucial in races where you want to keep your glycogen reserves as high as possible for the final

I really noticed the setting differences on the Esses.

Hi Shane what gearing are you using in the video? And what gearing are you using ridning on Zwift Mountions do you use the slider for trainer difficulty? Love watching your vidieos on the Channel.

Hi Shane Out of curiosity I reduced my trainer diff from 100% to 0% and did a test ride on Watopia Hilly Route. Sure enough after hitting the first climb (which comes along quite quickly) I felt no resistance change and upped my gears and cadence to maintain watts, which I found alot easier on the legs !!!! At the top I did a U turn and came back down,...expecting to keep pedaling as the downhill should still be 0%. Instead my avatar SPED UP to over 50 kph with hardly any input from me !!! My avatar even adopted a tuck position !!! This must count as a massive advantage for anyone in a race @ 0% trainer diff......... or even users with dumb trainers and power meters. Have you experienced the same ?? Am I missing something ?? I have a Tacx Neo.........Cheers Steve

Would like to see a down hill vid , when racing the higher % is great uphill but down hill is brutal , spin fest and loose ground

Great video! What about descending? Sounds like a trainer difficulty of 0% could prevent you from spinning out, and therefore reach a wattage you couldn't normally reach in real life / at 100% difficulty.

Am I the only one who keeps it on 100% because I'd rather feel the changes in gradient more as its more immersive and challenging?

So, the bigger question. If you had to climb 5% for 3 or 4 hours, which setting are you going with? Would seem to me that the preferred option would be lower difficulty results in higher cadence, less latic acid, longer ability to pedal.

as I see it. if you have a 12/25 casette you set it low. if you have a 11/32 you set it high. so it simulate a low medium or high gear :)

I leave it at 100% with a 50/34 and 11-32 (2x9 Sora set up).... If I tackle the Stelvio or Ventoux on Wahoo RGT I'll consider lowering TD to 75% which is to take into consideration that if I ever did these mountains in reality I'd probably swap out for an 11/36 or even 11/40 cassette.... I don't mind working the gears on a hilly course- keeps you focussed on the view ahead and the profile, and probably ensures a more fair and even wear on the cassette rather than sticking to just a few gears (or worse in ERG, one gear....)

question: at around 0.28 in the video, we can see a choice for routes. Is that gone now in ZWIFT ? I dont see this anymore. I only see the default and I have to use the Zwift companion app to select the other directions to see where it would lead me

I have ride 100% trainer level all the time. I want to keep realism level perfect as possible. It's part of a cycling to feel pain in a legs. Gives a pleasure ;).

The gear changes so the cadence changes . One side benefits a high cadence the other a low cadence . It effectively gives you a broader range of gears .

I’m still a little confused ... I get the watts need to be the same but does the higher difficulty level mean that it’s harder on your legs? I guess that’s when you work through the gears right to make it easier? do you have a general preferred setting that’s best of both worlds? ... or a preferred setting for training vs racing vs a more chilled ride?

Thanks for clarifying that the setting makes no difference in game but how did the effort feel to the meat motor? How were the two runs different to you?

I personally find leaving it at 100% makes it feel more like real cycling.

It is quite old video, but the subject is still hot. Could you provide average power and normalized power from both tries? I don't understand understand why did you need to change the cadence with difficulty=0, when you hit 350. Is there any difference in behaviour with Neo? (where the trainer bahaves as in ERG mode)

I have found that on rides like the AHDR humpday ride I fare better in the after party on 80% trainer difficulty rather than the default of 50% because I can push harder into the resistance on the little rises. Even though the average power required is the same for both settings I think i produce power better when I need to generate torque into little power climbs rather than increase the cadence. I'm sure other people would have opposite experience.

So the question for me as a heavier rider with a FTP lower than 200 is; a) Do I ride at min on the slider and spin to work cardio only? or b) Have the slider on max and increase my tolerance for grinding gears at low cadences? My knees often suffer at low cadences when climbing outside. I am already running a 50/34 with 11-32. Will training the knees work or just result in injury?

It is a way of making the cassette more flexible.

It's a lot easier on a lower trainer difficulty for those of us who can only manage half that power output and would otherwise run out of gears! Try the test with a CAT D rider who might have yo grind away at 50 to 60rpm. Would they end up slower yhsn the guy on a lower trainer difficulty who can maintain 85rpm? PS, as many have said you are a legend. I can maintain 350w for just about 1 minute after which there is no way I would be talking!

You didn't say which you liked more. Any preference?

Big argument on Zwift Riders (FB) after the Ineos race up the Alpe. Someone was claiming Rohan won because he had is difficulty slider set to ZERO (but had no proof). Needless to say there was a lot of fun being had in the responses. Someone ultimately posted a link to this video, and it seems to have quieted things down.

I've noticed your RPM v.s. Speed drift apart even though you are staying in the same gear. Do any of the trainers lock the speed to rpm tighter?

Its almost like having more gears in the pocket turning the difficulty to less than 100%? Being able to spin the legs in the same gear you have to grind when set to 100%... the wattage might be the same just the cadence possible in the same gear changes?

Sorry if this was addressed earlier, but have you tried using Instant instead of 3 sec average for power display? I find the feedback is better for maintaining a given power during intervals which might seem counterintuitive, but the smoothing creates a lag that I end up chasing more. The refresh rate on the display seems the same, just more accurate.

Question - Having that slider set at 0% affected the Kickr Climb, right? It didn't go up and down as much?

I always go with the following. If you have 11+ gears I set to 100%. Anything less I proportionally (roughly) decrease it. No gears I would set to zero or close to it.

Insightful video, as always. Next question... Does the slider affect how much incline and decline you get on the Climb? For example, if you have the slider set to 50% and you're on a 10% ascent, does the Climb think you're on a 5% ascent and only rise half the amount it should?

Interesting. What effect would the trainer slide have on a non ERG mode trainer if any? Would it for instance, calculate the riders profile and slow the virtual wheel speed if set to 100%? Asking as my 5yr old daughter is hooked using it for her monthly Race at your own pace medal. She's using a 20" wheel and pedalling like merry to achieve her 25 mile goals each month particularly when the road goes up on Zwift.

Hi Lama, I just got a smart trainer and I watched this video for the second time. My new trainer is the Tacx Flow - probably the chepaest smart trainer on the market at the moment - and it has maximal gradient simulation of 6%. I thought that if I'd set that trainer difficulty slider to 100% it would just (as obvious) simulate everything up to 6%, but I also thought that if I'd change that slider to for example 50%, it would give me that real 6% grade simulation on a virtual 12% slope (so literally it would seem like it's able to give me wider range of resistance levels). I thing it sounds logical, but today I've tried that for the first time and it always stops giving me resistance after I reach virtual slope of 6%, eventhough the trainer is (or at least should be) able to simulate steeper slopes at the time. Could you please check that for me (ideally on some lower end trainer like my Tacx Flow) if it really is this kind of 'stupid' or is it just my problem? Thank you for your answer.

Still not 100% sure I understand. Let me know if I got this right. At 100% you would need to use a gear just like you would in real life climbing at 7% to produce 350 watts. At 0% you could use whatever gear, even 50x11 and spin it up to produce the 350 watts.

Shane, are you a world class biker? It looks so easy for you. I’m an 82 year old “athlete” and I am having difficulty even maintaining 150 watts. Am I doing something wrong or am I just that pathetic? I was still doing ultramarathons until last year so I believe I’m in pretty good condition. Any thoughts?Also, I cannot locate the slider bar for trainer difficulty. Thanks. Tom Reich.

Good video. Seemed like your cadence was around 85rpm in the 2nd attempt vs. c. 75rpm in the 1st?

Shane, just getting into trainers and indoor biking. Budget at the moment forced me to start with Bkool go and an average 10 speed bicycle. On this setup although I peddle very fast and get good rpm my watts are relatively low and my bike travels and an unrealistic slower than expected speed. Other bikers pass me all day long. Any idea what I need to do to correct this ? is it just poor equipment or is there a setting somewhere I can tinker with ?

@shanemiller quick question... I have my difficulty set at 50%. Should I set it to 100% for a more realistic ride on my Tacx flux?

Ok simple question do you go faster and more wotts with erg mode off. Please 🙏 help newbie to zwift.