The most recent Zwift update added two buttons to the action bar:

What do they do exactly? Zwift’s release notes don’t mention them, so I decided to do a little testing…
Getting Them To Show Up
First things first: chances are you aren’t even seeing these buttons in your action bar. The action bar’s options change based on what you’re doing in Zwift, and these new buttons only show up (as far as I can tell) in one very specific scenario.
First, you have to have a smart trainer paired as “controllable”. Next, you must be in workout mode. Lastly, you have to have ERG mode turned off.
So these only show up for smart trainer users who are doing a workout with ERG mode turned off. But what do they do?
Resistance Changer
The buttons show a smart trainer with a + or – sign next to it. Mouse over them and the + says “Harder” while the – says “Easier”. Click the + button and your trainer resistance will increase. Click the – button and it will decrease. You’ll even see a little vertical resistance meter moving up and down to the right of the main center HUD element:

So these are trainer resistance adjusters. Interesting. But why has Zwift added this option to the game? I have three theories…
Theory 1: A Niche Feature
It’s possible that the current scope and functionality of this feature is all that’s planned. If so, what problem is Zwift trying to solve?
It would be a very niche issue: if someone was doing a workout on a low-geared bike (such as a MTB or city bike) and preferred doing workouts with ERG turned off, this feature would be helpful.
In this scenario, the workout may ask you to put out a higher number of watts (say, 450W) but you may not have a high enough gear to give you the resistance needed to hit those power numbers. Bumping up your trainer’s base resistance level would basically make your bike feel like it has higher gears.
Theory 2: An Unannounced Beta Test
Perhaps this is a new feature Zwift plans to roll out to the action bar in all scenarios, but they wanted to test the feature with a more limited audience. Having it only show up when ERG mode is off would let riders “in the know” test the feel and functionality of the resistance changes before a larger releases.
Theory 3: A Mistake
Lastly, there is the possibility that these buttons are still under development and weren’t supposed to be included in the public release.
Potentially Useful

My hunch is that theory 2 or 3 are correct, and Zwift plans to roll this feature out to the action bar in more scenarios. At least, I hope that’s the case.
Why would Zwift release such a feature? Because it lets you dial in your mechanical gearing for a better experience. Depending on how your bike is geared you might spin out on hard sprints or descents (gearing is too low overall) or you might grind to a halt on steep climbs (gearing is too high overall). This has always been a problem for people who ride mountain bikes on Zwift (real ones, not virtual ones), and while virtual shifting solves the problem, it only solves the problem for people who own a Zwift Hub trainer with a Click or Play controllers for shifting.
Adding these resistance-changing buttons to the action bar in (almost) all ride scenarios would let all smart trainer users dial in their gearing nicely. The only time it wouldn’t make sense to show the option would be while doing a workout in ERG mode, since the game is setting the proper resistance automatically.
It’s worth noting that Zwift is saving the resistance setting between sessions, too. This indicates that Zwift sees this as a way to dial in your trainer not just for specific times on specific workouts, but for your training overall. So I’m hopeful that this feature will be available in more scenarios soon.
Questions or Comments?
That’s my take on Zwift’s unannounced action bar addition. But what’s yours? Share below!
Would be nice if ERG mode would always be possible to choose. Then you could pick any route and combine these buttons to your preferred own workout without the hassle of creating a workout first.
You can – just choose “Rider’s choice” workout
Didn’t kniw that, thanx!
That’s been around forever? It’s just before the icon was a slope. It’s also changeable using the companion app.
Correct, I use these buttons all the time (and the slope buttons before) when doing long high intensity intervals. ERG mode with my trainer can be very punishing if you let off the cadence just a little so turning ERG off and adjusting the resistance with the button makes it so I don’t need to think about what gear to be in between intervals. I just turn ERG on and off.
glad you said this – thought I was going mad as had always been able to do it. I’ve used it before to get a suitable resistance for the power I want whilst in the middle of the cassette. Pretty sure every training platform has it. Often referred to as “Grade”
How does this differ from the buttons that were previously only on the companion app, that allowed you to increase or decrease “incline”?
Is this just remote access to TD ?
Nope!
“Adding these resistance-changing buttons to the action bar in (almost) all ride scenarios would let all smart trainer users dial in their gearing nicely.”
Agree. I always wanted to have the possibility to set a higher base resistance in a race so that I don’t have to use my hardest gears all the time which make much more vibration and noise and annoyed my neighbors.
I’ve used them already and, as you mention, I find them to be really helpful, as I gear out sometimes with my bike. Also, on the opposite hand, I love the possibility during a workout, to reduce the strenghts of the trainer straight from the console, while maintaining the watt goals
The equivalent of the resistance buttons already exists in Zwift Comapion, called “Incline”. My guess is they wanted to give riders not using Companion a way to adjust the resistance when doing a workout with ERG off.
Hey!
I use them occasionally to change the FTP setting in a workout. If the interval is set for 2 min @ 250 W, two clicks drops the number to 245 W and shows the % of your FTP change as well.
That’s a different button. That’s the FTP bias setting.
The answer lies (ironically) in indieVelo’s Virtual gearing explanation. Communication still not a strong suit at Zwift. Why virtual gearing is useful -> https://wiki.indievelo.com/docs/trainer-feel/
I hope they roll this out more widely. I find that I struggle to find a gear sweet spot in certain circumstances. For example if I want to hold a steady 200w at the moment I find myself cross-chaining either with big ring and a large cassette ring, or small from ring and very small rear cog. Either is suboptimal and causes noise. If I dial it into being in the middle of the cassette then that would be great.
Just had a case yesterday trying to stay in a groupetto where in one gear, cadence was high, yet I was slipping out the back of the group. One gear up, I was at a comfy cadence, but blowing out the front of the group. Being able to coax up or down would be nice.
You’ve always been able to do this from the companion with the plus or minus bias control
Bias control is totally different from a +/- resistance button.
But as James says above, it appears this option was available in Companion, but as a +/- incline button. Interesting…
Computrainer had this feature many years ago, and I believe Wahoo’s phone software too. When riding a workout without ERG, your trainer is basically set to be riding at 0% incline (also why you don’t feel the terrain in such a workout), using these buttons just changes the incline that the trainer is set at, making it feel harder, or easier. This is also why the icon was a ramp in the Companion app – it’s adjusting to a higher incline, or lower decline.
So it’s virtual gearing for standard geared bikes….but that way you don’t need to physically shift…
that what i have understood too – a bit like Zwift Cog but for any turbo trainer
A bit like Zwift Cog but no need to buy the Cog or clicker – Ah 🤔
I like that…could stay in the little ring but use this to shift. Although for ipad clicking to bring up the menu, then choosing +/- isnt too efficient! I’m sure it will work with the Click eventually.
I would really like to see this across all of zwift and soon. It would improve Sweet spot on gearing and also no more indexing and easy physical bike changes. It all sounds a bit like zwift cog?
Is this what Nathan Guerra referred to in his podcast? Virtual shifting for all, in the making?
if it’s virtual shifting then shortcut keys would come handy…
How would using this affect an Everest? My poor gear setup isn’t ideal for using the alpe, don’t have enough gears, this could solve that problem…
For anybody at Zwift or with pull at Zwift here’s the feature we actually need – the ability to have a workout mode HUD while still having terrain gradient simulation. You know, the way that you actually do workouts outdoors in the real world. I’d like to have countdown interval timers and power targets displayed on zwift instead of having to run them on my head unit and then having to delete the duplicate ride from Strava or TrainingPeaks.
You mean a Climb Portal for workouts?
@TheStansMonster So just do any workout in Zwift and turn off ERG mode then…….. unless I am completely misunderstanding the question here…… That would do exactly as you describe showing the workout timers and targets on screen but meeting the power required is down to you and not set by the smart trainer which just reacts to the terrain 🤷🏻♂️
These buttons have been there and I’ve been using them for a long time, mainly to control the resistance such that the resistance feels the same when entering/exiting a non-ERG workout from/to free ride mode, so that cadence stays the same.
The feature has always been keyboard accessible with the +/- buttons (I know: this is not the FTP bias – use the pageUp/pageDown keys for that). I use it often in workouts because I usually disable ERG mode. It works like a virtual gear shifting that allows me to fine-tune the rpm for an interval. So for example, I’m doing an interval (ERG off) and I’m targeting 300w at 95rpm, but I’m cruising along at 300w and 90rpm. To increase the cadence I could shift to a lower physical gear or hit the minus button to do a virtual shift.… Read more »
as someone using an older 1x bike on my trainer this would be a great feature. I always have either too light of a gear on sprints or too hard on the long big climbs.
Does it work despite being out of training mode?
I don’t think so, would be nice if it did.
This feature has existed for years, but not as an icon. You had to be in workout mode and press the + or – on the keyboard (PC). I found that it worked in Workout mode and was good for adjusting the resistance slope pending your gearing. If I am doing small ring work, but need to be at a specific cadence and power, but running out of grease, I could change the resistance + and the resistance slope increases. It is like having more gears. I’m sure this is the same for mountain biker set ups in workout mode… Read more »