Trainer Difficulty on Zwift: How Much of a Bigger Granny Gear Does 75%, 50%, and 25% Provide?

Trainer Difficulty on Zwift: How Much of a Bigger Granny Gear Does 75%, 50%, and 25% Provide?

Editor’s note: this article originally ran on Jordan’s website at meatmotor.com. We appreciated Jordan’s alternative view of Trainer Difficulty and loved his willingness to sweat for science, so we asked if we could share his findings with our audience.


Jump Straight to the Gearing Results

Perhaps there is nothing more misunderstood in the Zwift world than trainer difficulty.

Some people have (wrongly) postulated that if they are racing with the Difficulty slider at 100% against someone racing at 50%, they are at a disadvantage. This is not mathematically true. In Zwift, watts are watts. The difference is the feedback in terms of resistance your legs get on an incline (and decline).

On Zwift, keep in mind you have a virtual rider who is propelled by watts. You also have the real world you in which you create those watts.

There are two ways to generate more watts. (1) Press harder on the pedals (force/torque) or (2) spin the pedals faster.

Zwift Trainer Difficulty is said to be a decrease in the gradient of a hill in terms of what is presented to your legs in terms of resistance on the trainer.

  • At 100% Difficulty on a 10% gradient, you feel the full 10% in terms of pedal resistance.
  • At 75% on a 10% gradient, you are only experiencing a 7.5% gradient in terms of pedal resistance.
  • At 50% Difficulty, that hill is now a 5% gradient in terms of pedal resistance.

And so on…

Here are how things even out. Your on-screen-rider is STILL going up a 10% gradient and needs that amount of virtual watts to get up the climb even though your Trainer Difficulty can make the gradient feel reduced to you the real-rider.

So if you are racing someone and they are at 100% difficulty, and you are at 50%, their trainer resistance will be higher, and they will be putting out more force and watts than you at the same cadence as you. To keep up with the 100% rider in the same IRL (in real life) gear as you, you will need a much higher cadence to output the watts needed to drive your virtual rider up the climb.

So a good comparison/analogy is to see trainer Difficulty as your available gear selections. But realize that your available gear selection changes based on the gradient of the hill.

At 100% difficulty, you are locked into your real-world gearing on your bike. So if you are riding a steep climb in your granny gear of 34×28 is too difficult to spin at 80 RPM cadence, all you can do is reduce your cadence. Just like IRL, you’ll be slogging up that hill at some incredibly low RPMs (aka the dreaded 50 RPM climb). This is usually not the most advantageous physiological means to get a bike up a hill. There is a lot of taxing on the muscular system at 50 RPMs cadence.

But, with the Difficulty reduced to 75%, you now have a bigger granny gear at your disposal, and at 50% an even bigger one. You can now spin at higher cadences than you could on your real-world gears. (But don’t forget, you’ll have to spin faster to go the same speed online).

But Just How Much Bigger Are the Gears at Each Percentage?

Ahhhh, time for an experiment and a report.

Test method:

  1. Climb up a specific segment of Alpe du Zwift that is a 10% gradient at the same cadence but with different difficulty settings. In this experiment, cadence is the constant in the equation. I chose 80 RPMs because it seems like a good balance between grinders and spinners. I chose the 10% segment because that is a solid round number.
  2. Trainer Difficulty is the variable. The test was performed at 100%, 75%, 50%, and 25% difficulties.
  3. Speed will be the outcome. Spinning at 80 RPMs at 100% difficulty makes your virtual rider go faster than spinning at 80 RPMs on 75% difficulty. So the speed in mph is the important piece of the experiment.
  4. Once we get the speed for each difficulty level, we can reverse engineer the speed at cadence to approximate the gear using Sheldon Brown’s Online Gear Calculator.

Note: I ran this test twice at each Difficulty, but it needs more repetitions to be definitive. Also, the gradient does affect the results. A lesser gradient would be a smaller equivalent gear difference. But 10% is a pretty classic climbing percentage, and Alpe du Zwift is the most iconic climb (granted the overall ADZ climb averages 8.5% overall). When I have time, I’ll rerun this on this segment and at other gradients.

Setup data for the experiment:

  • 77 kg rider on Zwift.
  • Sheldon Calculator inputs using 700ccx25 tire and 172.5mm cranks. Yes, I am using a direct drive trainer IRL, but I had to pick something for that value.

Test results:

  • Runs at 100% Difficulty and 80 RPM Cadence on 34×28 (2 run average)
    Speed achieved in Zwift 7.98 mph
  • Runs at 75% Difficulty and 80 RPM Cadence on 34×28 (2 run average)
    Speed achieved in Zwift 6.54 mph
  • Runs at 50% Difficulty and 80 RPM Cadence on 34×28 (2 run averages)
    Speed achieved in Zwift 4.65 mph
  • Runs at 25% Difficulty and 80 RPM Cadence on 34×28 (2 run averages)
    Speed achieved in Zwift 2.69 mph

Then we reverse-engineered the equivalent gears on Sheldon’s calculator.

The Results

Difficulty SettingGear Equivalent on 10% ClimbWatts Required for 80 Cadence
100%34 x 28 (real-life test gear)311 watts
75%34 x 33248 watts
50%34 x 46177 watts
25%34 x 77 (aka the whopper)93 watts

This is what you really wanted to know. Thanks for sticking around.

Summary and Insights

You can get some whopping big granny gears in Zwift using the Trainer Difficulty setting. For riding inside the Zwift world, you can virtually swap out your cassette just by reducing the percentage. Spin like Froome or grind like Ulrich, whichever you prefer to go fast.

On a 10% climb, reducing the difficulty to 25% means that you have a massive gear available to you. Granted, you will need to spin the snot out of it, because at 80 RPM and 2.69 mph it will take you 2 hours and 47 minutes to arrive at the summit. Of course, you can always run at 25% difficulty and simply use a bigger real-world gear. Heck, run your big ring and feel like a pro.

When racing, you can reduce Trainer Difficulty, just realize on every incline you’ll have to spin faster than your competitors due to the decrease in gradient effect. As you see in the chart above, you are at 25% difficulty and your opponent 100% spinning at the same cadence, you’ll get dropped like a hot rock.

One caveat, if you are going to do some massive real-world climbs, you might not want to not dial down the difficulty on Zwift. Instead, get used to grinding your real-world gear limitations once you run out of gears.

Questions or Comments?

Share below!

About The Author

Jordan Fowler

Jordan's Myers-Briggs INTJ, Enneagram-5 personality ensures he loves data, data on a spreadsheet, and science. He has experience as a head coach of swimming and a distance running consultant for promising high school athletes. Jordan has been participating in cycling and triathlon since 1989 and is a "descent and tailwind" specialist. His site meatmotor.com breaks down the latest sports science studies to help you become a faster cyclist and endurance athlete.

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ExerScreen
4 months ago

This needs to be pinned at the top of every online forum. And no Zwift user should be allowed to post anywhere until they pass the Trainer Difficulty Exam.

David Riley
David Riley
4 months ago

Climbed Ven-Top yesterday and ended up with 25% TD so I could spin in the high 60’s at 11%. Don’t think I’ll be doing Ventoux any time soon.

Volker
Volker
4 months ago
Reply to  David Riley

I was thinking exactly that when going up Ven-Top at 50% the other day. Need to loose 10kg before ever attempting IRL Mt Ventoux. Some day I will re-try Ven-Top at 100%. Some day, just not today. 😊😊

Frank Drennan
Frank Drennan
4 months ago

I feel the key point here is being missed; if you are putting out 200w, it does not matter what gear you are in IRL or what the trainer difficulty is set to, your speed will be the result of the power, you weight and height, the gradient, and the zwift algorithm that combines these factors. The most practical result of reducing trainer difficulty is that you do not need to change gear as much to maintain power at same cadence. At the limit, if trainer difficulty was zero, there would be no change in trainer resistance with gradient. IRL… Read more »

Miguel
Miguel
4 months ago
Reply to  jordan

Keep in mind that really easy gears are also inneficient and impossible to hold irl because loss of balance.

Stu
Stu
4 months ago

Nice experiment. I would like to have it tested another way around. Set the watts at e.g. 250w Put the bike in granny gear Record the different cadences at 100%, 75%, 50%, 25% and then calculate the equivalent gear ratios for each difficulty. This would then show that a 34/28 is equal for example to a 34/30 at 75% This test could be done for all the common granny gears. 39/25 etc Somebody could build a calculator. Enter your desired climbing watts, enter your current granny gear, enter the max gradient of a climb and the Trainer Difficulty could be… Read more »

Jason Masterman
Jason Masterman (@masterman_driving)
4 months ago
Reply to  Stu

Definitely agree. The article states you need to spin faster but gives no clue as to how much. 311w is 80rpm @ 100% 126rpm (???) @ 50%.

Stu
Stu
4 months ago
Reply to  jordan fowler

The maths would indeed become complicated (without the algorithm)! That is why I said someone else should come up with a calculator 😉
Simply, Zwift should never have used the word difficulty. It could have been implemented as a granny gear calculator, but then they might have confused the novice riders and insulted grannies! A no win situation….
But thanks again for this post. I think the link to this article will be pasted often in the FB comments!

Lance Johnson
Lance Johnson
3 months ago
Reply to  Stu

I had the same thoughts as well. I have a NEO Bike and can electronically change the gears pre-ride. I always thought what gear should I swap for 32 for…maybe a 40 for steep climbs.

Tony Filipe
Tony Filipe
4 months ago

One issue that still puzzles me is; back when I started on zwift, the trainer dificulty was at default value” whatever that normally is” back then I was putting out crazy watt number like 450/470 watts, than I became awhere of the trainer dificulty setting and I set it approx 80/90%. Since than I started to see more realistic wattage from my training session… any one able to explain this please! really would like to understand it.

James Eastwood
4 months ago

There is another thing that is important to mention, and that is inertia. The better smart trainers simulate the ‘feel’ of a climb by altering the inertia and the effort required to overcome that inertia and spin the flywheel. It is a simply a linear increase in resistence (which is the case for a wheel on trainer). This is another reason why it is important to state that what changes with TD is the gradient sent to the trainer. That gradient can be interpreted by the trainer in different ways, but on a good turbo like my Tacx Neo Smart… Read more »

James Eastwood
4 months ago
Reply to  James Eastwood

That should read ‘It is not simply a linear increase in resistance’

Pauly D
Pauly D
3 months ago
Reply to  jordan fowler

Sorry Jordan but this is not correct. There are physiological differences between riding on the flat and riding up a steep gradient, this is why people tend to self-select a lower cadence on a climb even when not in their lowest gear. This is also the reason why trainers have heavy flywheels, because it feels like riding up a 20% slope through sand without it. There have been a few scientific studies looking at the differences (I can’t be bothered finding them now) and it comes down to inertia. When riding on the flat at high speeds people tend to… Read more »

Nathan Lipke
Nathan Lipke
4 months ago

It would be cool to see downhill equivalents to. Is riding at 25% TD like having a 52×5?

Mark C
Mark C (@rdcyclist)
4 months ago
Reply to  Nathan Lipke

No, it’s the opposite. You need to run a taller gear to make up for the lower TD. This effect is much more noticeable during flat workouts with specific wattage requirements. When we’re supposed to be generating 120 watts in a group you’ll be in your top gear spinning your ass off.

Ron Buch
Ron Buch (@ronbuch)
4 months ago

This is great info. I always feel like I’m cheating using the 50% setting. But, I’m also riding a 53/39 crankset and an 11-25 cassette, so 50% just gives me a granny gear like many are using IRL.

Jonathan
Jonathan
4 months ago
Reply to  jordan fowler

Yep… Learned the hard way that I could have really watched my cadence/power when training on all de Zwift all those times before trying to PR up my Diablo. It was a big “derp” moment for me. Lol

dan
dan
4 months ago
Reply to  Ron Buch

i run my power much lower; so im never off the big chain ring; and i never have to worry about dropping a chain

Michelle A
Michelle A
3 months ago
Reply to  Ron Buch

Yep I just realised that my trainer bike set up is such that I could turn down TD a bit for those unrelenting climbs and it’s not cheating! (53/39 and 11-28) My new roadie for outdoors is a bit easier

Rob
Rob
4 months ago

good post, key take away for me – racing – As you see in the chart above, you are at 25% difficulty and your opponent 100% spinning at the same cadence, you’ll get dropped like a hot rock. So true need to pay attention and ramp up on every climb to not get dropped fast

Hybrid Noob
Hybrid Noob
4 months ago
Reply to  jordan fowler

Having always raced on a dumb trainer with the same pm I use on the road, you very soon get used to looking ahead and anticipating the increase in watts with every kick up 🙂

travels
travels
4 months ago

How does this factor in muscle fatigue? A higher %TD results, inevitably, in lower cadence, which, in turn leads to quicker muscle fatigue. Studies have shown that muscles are far less fatigued at 100 RPM than at 60 RPM while pedaling at at the same watts output. As a result you get tired more quickly at lower cadence/higher TD and thus slow more quickly. From a personal experience perspective, I spent my first two years on Zwift at 100% TD; having dropped it back to 50% since 2020 started (after a long chat with a fellow Zwifter) I find my… Read more »

Ian
Ian
4 months ago
Reply to  travels

Opposite here. I find it much easier to maintain power at lower RPM. I can get a better FTP uphill at 60 RPM than doing FTP test on the flat at 100 RPM

Eddie Ryce
Eddie Ryce (@dundeeedd)
4 months ago

I’ll be honest on my last ascent of y 24 hour alpe Du Zwift challenge I went down to 25%

Olly
Olly
4 months ago

This is interesting article but does it miss one aspect of indoor training – at 100% gradient I usually have 1 or 2 gears spare when riding indoors compared to IRL.

I can spin “comfortably” up the alpe in 36×28 on 100% gradient, but doubt I could on 10-12% IRL.

Could just be me, different trainers, or general turbo stuff.

Andy
Andy
4 months ago
Reply to  jordan fowler

GCN did the comparison https://youtu.be/YaoqPzDtRbs

Olly
Olly
4 months ago
Reply to  Andy

Really interesting inside v outside comparison of alpe du huez/zwift but doesn’t answer the gearing question…

He mentions the average cadence difference overall between his efforts but also says he was out of the sadde more IRL where you’d expect lower cadence as a result

MATHEW M ROSE
MATHEW M ROSE (@matrose617)
4 months ago

This is so useful as it perfectly lines up with my IRL experience of finding that my preferred cadence of around 78 rpm runs up against my threshold on longer double-digit gradient segments as that equates to around 300w with a 28 tooth gear. I bought a 32 to try for longer, steep climbs, and it seems from the data that I could climb comfortably at sweetspot for a while on a >10% climb with those extra teeth (especially as I’m a bit lighter than the 77kg model for this test).

milhouse
milhouse
4 months ago
Reply to  jordan fowler

Oh my, is that considered low? Then I’m ridiculously low 😀 On my “best performing” outdoor ride recently (55.5 miles with 3,100ft of elevation gain completed in 2h55m/19mph average) I ended up with an average cadence of 66rpm. Personally, I find I can grind for hours no problem but really start suffering when I have to spin for long periods of time. Zwift has helped me get used to higher cadences, but left to my own devices I rarely stray above 70 😀

Craig Martin
Craig Martin (@viiich)
4 months ago
Reply to  milhouse

Funny enough on easy rides I’ll tend to be lower, low 80’s, but I usually spin 95-110 RPM in races, with sprints up to 135 RPM.

Buzz
Buzz (@jimbo_jim007)
3 months ago
Reply to  jordan fowler

Me and my mate mostly get in the 80’s every zwift ride….

Rob Miller
Rob Miller
4 months ago

A fun fact for TACX NEO 2 users … One cool feature of those trainers is that the trainer motor spins up when you go downhill which gives a touch of realism but I suspect my whizzing down the back side of many big climbs contributed to bearing failure in my unit due to the high spin rates for long periods. Credit to Garmin to replacing my NEO 2 under warranty but now when I’ve finished a big climb and just want to freewheel down I set my trainer difficulty to zero and enjoy the wear-free silence as I descend… Read more »

Stu
Stu
4 months ago
Reply to  Rob Miller

Another option is to unplug your Neo, that also stops the freewheel.
Easier than dealing with an apple tv remote! 😉

Kim S
Kim S
4 months ago

The professional cycling coach I worked with for 3-plus years taught me that riders should never be grinding up a hill at a low cadence. Instead, the winning play is to find a gear you can spin at about 90 rpm and use that for climbing. I find I’m actually faster up hills both outside and on Zwift using such an approach. As a result, I love the trainer difficulty setting and have left it at 50% since the day i started Zwifting back in the fall of 2017. BTW, my granny on all my bikes is a 32–including the… Read more »

Dan Nicolescu
Dan Nicolescu (@dan-nicolescu)
4 months ago

There is one less explained element here. You always assume the comparing riders are in the same gear combination, but one with lower difficulty can output the same power if they are in a higher gear. I personally believe that the difficulty can help with reducing the amount of gear shifts. Also, as a good analogy, one can think of climbing at a reduced difficulty by imagining zigzagging up instead of climbing straight. You experience a smaller incline, but you have to go longer. IMO, the only impediment is that one can get performances in Zwift that cannot be replicated… Read more »

Jonathan
Jonathan
4 months ago

I think it’s also important to note that a lot of folks are still using wheel-on trainers and the effect is the same– you end up being able to “spin” up the steep ascents if you want because your own gearing determines your difficult setting. But you would still have to either soon higher at same getting it else bump up the gearing to make the same watts/speed up the hill as sometime on a smart trainer. Would be fun to see the pseudo “difficulty settings” on a wheel-on trainer at different great ratio choices.

Montanaben
Montanaben
4 months ago

This is good stuff, though now using my gravel bike (30-34 granny on the kickr core) I can just set it at 100% and forget it. Nice to have climbing gears even in the virtual world with Ven-top…

Jan C.
Jan C.
4 months ago

The chart mentioned above explained a different perspective i.e. gear equivalent for each TD settings at 10% gradient.. But lets look at it at a power output perspective, do you agree that for a rider ascending at a 5% gradient with 100%TD, will yield the same effort using the “Same Gear” if the same rider ascends at 10% gradient with 50%TD, maintaining an output of 200w and 80rpm?? Basically answering the ultimate question, whether the change on the % of a TD “virtually” (assuming a 10% grad): (1) changes/decreases the Gradient (although the actual gradient will still be displayed) on… Read more »

William Fracalossi
William Fracalossi
4 months ago

Darn you! Its 321 am EST and I’m reading @ mathematical formulas and bikes. But I’m really here to thank you for using and posting Sheldon Brown’s gear calculator and just mentioning the beloved East Coast cycling legends name. Every couple of years I get stuck wandering around his archived pages online, and lament never meeting such an interesting and intelligent soul and cyclist. Thanks for the memories ! Great article! (I’ll read it again at noon w a few cups of Joe in me!)
.

Darryl Jenks
Darryl Jenks
4 months ago
Reply to  jordan fowler

Fellow Sheldon-loving Texan here. That man was a real gem, and a kind soul to boot!

Ogg
Ogg
4 months ago

I’ve always explained this as a virtual front chain ring – as it does affect all gears.
I’ve still had to explain to my S/O about 20 times that it isn’t cheating!

J Pamplin
J Pamplin
4 months ago

Interesting article. But I’ll say this – regardless of how it works, I can climb alpe du Zwift a hell of a lot faster with trainer set to 20% than if it was 100%. It didn’t make much of a difference when I had a basic, wheel-on trainer but now I have a Kikr core it makes a huge difference. No question about it, if I’m racing against someone set at 100% and mine is set lower, I’ll have an advantage.

Keith Nichol
Keith Nichol
4 months ago

Great stuff. Thanks

Alan S
Alan S
4 months ago

Your solution only uses watts as a variable, but most riders play with TD so that climbs become comfortable. At that point they want to know how TD virtually changes their cassette, and what gearing would they need IRL to ascend a particular climb with the cadence used in Zwift. A generalized table can be created using a riders actual gearing at a specific TD and grade showing the virtual changes in their cassette as grade increases. This should be easy to program and am surprised it hasn’t been done already.

Alan S
Alan S
4 months ago
Reply to  jordan fowler

Your article is focusing on experienced climbers getting efficiently up climbs with their preferred cadence. I was speaking to cyclists who do a big climb in Zwift and wonder if they could do a big climb IRL. The lowest gearing you use is 34/28 which is moves your rear wheel 1.21 rotations where many novice riders using TD setting under 50% would need a 1 X mtn bike gearing that allows gearing ratios under 1 to ascend IRL. The table I suggested would just give zwifters an awareness of the virtual gearing they are using.

Jhsvdm
Jhsvdm
4 months ago

Fantastic post. Really enjoyed reading it. And I agree with your end advice. Keep closer to real world settings if you want to climb in the real world. As I started reading I thought I should get away from default setting. Been up Alpe d Huez on 34/28 and was quite doable. Have the gearing on my bike on the trainer. Wtf. Loved the humor too. Lol.

Darryl Jenks
Darryl Jenks
4 months ago

There is a lot of taxing on the muscular system at 50 RPMs cadence.”

Yeah – isn’t that the point?

Juergen
Juergen
4 months ago

Does anyone know:
Is the difficulty setting only effective on climbs? Or does it also change the behavior for descents?
I wonder, whether you could simulate higher gears on a low difficulty setting to still be able to pedal downhill (as the simulated gradient is lower), while at a higher difficulty setting (as the gradient is higher) you cannot spin fast enough to put pressure on the pedal.

milhouse
milhouse
4 months ago
Reply to  Juergen

Yes, it changes the descents too. If you are on 100% TD it can be very hard to keep up with people on 50% or less TD when descending, because you’re spinning out and they can push more watts against the extra resistance they’re feeling.

Eleri
Eleri (@eleri)
4 months ago

Thanks Jordan! Zwift changes my gearing because IRL I have the appropriate gears for a 650c wheelset. But that’s about 7.5% lower gearing than the same groupset on a 700c bike. Zwift takes wheel size out of the equation because trainer difficulty assumes 700c because that’s the vast majority, so fair enough. It’s taken me a few years to realise this though! Trainer difficulty can help level that out. But it’s trial and error because I can’t work out what the realistic compensation amount is. I don’t think it is 92.5% (i.e. taking on 7.5%) and anyhow, that slider isn’t… Read more »

Eleri
Eleri (@eleri)
4 months ago
Reply to  jordan fowler

A Wahoo Kickr, Gen 1

Buzz
Buzz (@jimbo_jim007)
3 months ago
Reply to  Eleri

Zwift works on power, so wheel size is irrelevant to the trainer putting say a 200w load onto your bike. If we used a wheel on trainer, we could ride Zwift and the trainer would put a 200w load on the roller whether we had a 650 or 700c wheel. What we need to compensate for is the change in rollout gearing. If we ride the wheel on trainer and our threshold wattage up a climb is 250w for our 650 wheel with a 34/28 gear combination, that same 250w with a 700c wheel will make that 34/28 gear combination… Read more »

B.Q
B.Q
4 months ago

Can you re-do this test with the Stages Bike using the Dream Gears?.. lol.. just kidding.. great article!

Carl Scholtz
Carl Scholtz
4 months ago

Curious. The numbers in the article do not correlate exactly to the “unmarked” slider position estimate percentages, ie 50% does not appear to give 50%, etc. Practical experiment up Ventoux with a buddy this week. We rode adjacent all the way, no idea of bike gearing, same W/kg, same speed, 90 minutes duration. Rider A: 90kg. Avg 240W, 2.7W/kg. TD 100%. Avg cadence 77 Rider B: 75kg. Avg 200W, 2.7W/kg. TD 30% Avg cadence 84 I expected much bigger differences in cadence, ie at “30%” I expected to feel 3x easier or have triple the cadence. Not the case. Seems… Read more »

Flex Rampant
Flex Rampant
14 days ago
Reply to  Carl Scholtz

Paying no heed to the gear ratios is a huge flaw in your assumption.

trackback

[…] Meat Motor article is featured on Zwift Insider, the leading website for Zwift riders. The study, Trainer Difficulty On Zwift: How Much Bigger of a Granny Gear Does 75%, 50%, and 25% Provide, addresses a commonly misunderstood setting on the popular e-cycling app, the trainer difficulty […]

trackback

[…] Meat Motor article is featured on Zwift Insider, the leading website for Zwift riders. The study, Trainer Difficulty On Zwift: How Much Bigger of a Granny Gear Does 75%, 50%, and 25% Provide, addresses a commonly misunderstood setting on the popular e-cycling app, the trainer difficulty […]

Whiskey Tango Fixie
Whiskey Tango Fixie
4 months ago

As far as what you feel at the pedal due to the static (climbing) loads, the change in gearing is directly proportional to the change in grade. So going from 100% to 50% trainer difficulty is exactly the same as reducing the size of your chainring by 1/2 or doubling your rear sprocket. Exactly the same. Twenty five percent trainer difficulty equals four times larger sprocket, or 1/4 size chainring. One percent trainer difficulty equals 100 times larger sprocket, or 1/100th size chainring. That’s why it’s somewhat nonsensical to think about trainer difficulty in terms of gears when you get… Read more »

Lance Johnson
Lance Johnson
3 months ago

I believe the same effect on TD occurs when going down the Alpe. In other words a higher TD will make you go faster with less effort.

Eric
Eric
3 months ago

This is good but really just buy and put on the appropriate cassette in the first place and put at 100%.

Sean Standing
Sean Standing
3 months ago

Thanks for this Jordan, very interesting article. I use a LifeCycle IC8 indoor trainer on Zwift and as such have no TD option. My gear changes is all done by the turn of the dial but it does simulate a very large gear range. Downfall is though that I have to be ready for the hills and manually crank up the dial to increase the watts otherwise I am dropped very quickly. Always wondered what kind of gear set I would have to run IRL to to simulate my usual Zwift riding.

Matt 3595
Super Member
Matt 3595 (@straightlineboy)
3 months ago

Very useful article thanks. I use Zwift as a means of improving my outdoor riding so almost always ride at 100% TD because those are the gears that I’ve got outdoors and there’s some 20%+ slopes round here to get up! I don’t doubt that when I’m down towards 60rpm on the Alpe that it’s inefficient but I am improving, slowly! The chart at the end is useful because it tells me that anything below 75% is beyond the gearing that I could realistically fit on my bike (without a major reworking of the drivetrain) so I’ll use that if… Read more »

G L-S
G L-S
3 months ago

Thanks for this article. I hadn’t really been aware of this setting, and certainly didn’t understand it. Changed to 100% difficulty because of article, and after getting used to having to change gears all the time found it a more real riding feel – ultimately my average power was exactly the same as my similar rides just before the change

Aaa
Aaa
3 months ago

Does this ‘extend’ the gradient range trainers can do? Eg. My flux s tops out at 10%
With trainer difficulty at 50% will I feel the gradient increases in zwift all the way up to 20%?

Robo
Robo
3 months ago

Thanks Jordan for clarification. It is very useful and helpfu. I did Ventoux 100% and 10%. !00% was more demanding for legs but it was disaster to changing gears. 10% i could focus more to maintain power. So for ride for pleasure and for preparing for IRL mountains (as you mentionde) the higher difficulty the better. For racing it is better to use lower difficulty to keep in the pack instead of changing gears as sometimes there are less then sec and you are lost and race is over.

Paul
Paul (@paulgazey)
3 months ago

This article states that at 100% trainer difficulty you would feel the full 10% gradient and I could be wrong but I always thought Zwift halved any gradients therefore a 10% incline for example is actually 5% when the trainer difficulty is set to 100% and furthermore if you reduce your difficulty to say 50% then a 10% incline now is 5%

Jeffrey Doty
Jeffrey Doty
3 months ago

I assume it would be just another calculation to do a different equivalency, to show the real life gear necessary to push the 311 Watts at 80 cadence for the lower trainer difficulty levels. I would find that interesting, and it might help to drive the point home to people that still don’t get it.

Pat
Pat
1 month ago

How does this transfer to non-controllable trainers such as an Elite Kura, where it’s a case of resistance being ‘controlled’ by gear selection?

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