ERG mode does nothing


I have had a trainer for about a year but only tried Zwift the past few days and I am having some problems. I have searched for them and read some articles on other sites, but also found some topics about them here on the official forum, but none of them exactly describes my issue.

The problem I am having is with erg mode for workouts and how it works in Zwift. My experience from using Wahoo’s erg mode, from others describing it and from the Zwift website has given me a very clear picture of what erg mode is. The trainer sets the power target and adjusts the resistance according to how fast you pedal and the gear you are in. Unfortunately, my experience in Zwift with ergo mode is nothing of the kind. The way it has worked for me is that the trainer has set some arbitrary resistance and kept it for the entire workout. Regardless of me changing the gears or pedaling faster. Pedal faster? Higher power output. Switch to lighter gears? Lower power output.

I’ve also seen some people talk about erg mode being bad for short interval workouts due to not being able to change the resistance fast enough for ~10s intervals. My experience doing short intervals with my bike computer does nothing of the sort. It instantly changes power to match my cadence. Also, I never switch gears during those workouts.

I am ticking the box for erg mode when choosing a workout. I also made sure that erg mode was enabled on the companion app and by swiping up on the Apple TV remote. I also toggled it multiple times. Interestingly as well, when it was off I got the incline controls in the companion app and pressing up or down had an orange bar appear right of the top middle of the screen on the Apple TV. But as this bar was getting filled as I pressed the up arrow on the incline button and getting emptied as I pressed the down arrow on the incline button there was no change in the resistance of the trainer. Is this correct behavior? In that case, what are those controls for?

I’ll briefly describe my setup in case I’ve done something wrong.

Wahoo KICKR core 1.0.13
Wahoo TICKR (heartrate strap) 1.2.21
Wahoo cadence 2.0.19
Wahoo headwind 1.0.3
Apple TV 4K 13.4.8
Zwift app 1.0.53416
iPhone 13.6
Zwift companion app 3.16.0
KICKR core paired with the Zwift app on the Apple TV.
TICKR and cadence paired with the Zwift companion app on the iPhone.

Successfully did a spindown through the Zwift app after a few minutes of pedaling.

I am getting power, cadence and heart rate values consistently and without any dropouts.

The way it has worked for me is that the trainer has set some arbitrary resistance and kept it for the entire workout. Regardless of me changing the gears or pedaling faster.

This ^ (except for the “arbitrary” part) is exactly how erg mode should work in workout mode. The trainer holds you to a specific wattage regardless of your gear or cadence (if you change your cadence suddenly, you can induce a sudden fluctuation in wattage, but erg mode will bring the wattage back to the predetermined value quickly).

It isn’t arbitrary, however. The particular intervals / wattages / etc in workout mode are based on percentages of your FTP (functional threshold power), so you should have done one of two things before doing workouts: 1. do a handful of vigorous free (non-workout) rides so that Zwift can calculate or estimate your FTP for you, or 2. do a step/ramp test or an FTP test in Zwift.

Note that you don’t have to use erg mode when doing workouts, but the workout will still tell you what wattages to hold and when. Without erg mode you will have to shift gears, etc to maintain specific wattages, so I think most people prefer the simplifications that erg mode affords while doing a workout (don’t have to shift, can usually be at whatever cadence you prefer without affecting wattage, etc).

Since you mention you have paired your Core with the Wahoo app (which is where you should do the spindown, btw), are you sure you have DISconnected it? Make sure that your Core is paired to Zwift as both power AND controllable. Also, I would recommend that you NOT paid your Wahoo cadence sensor with Zwift, and just accept the cadence transmitted by the trainer (i.e.pair the Core as cadence, also). You can then pair your Tickr directly to Zwift through the ATV and skip pairing through the Conpanion app altogether.

With regard to the resistance, you say that it is the same through the entire workout. I’m guessing the workout you have chosen has multiple changes in power output? If so, you should definitely feel changes in resistance, at least if you maintain the same cadence.

Also, I don’t think those were incline controls. They were likely the workout bias controls to adjust up or down from your FTP level, depending how you feel.

Regarding one of the comments made by a Xavier: where is your FTP set? All workout intervals are based on a percentage of your FTP. So, if your FTP is set lower a 10% or 15% change up or down from that might not result in any real change in power needed, so it might feel like you’re just stuck on the same feel. So, definitely either set your FTP manually to what you think it might be, or do one of the FTP tests in Zwift to determine it.

Keep us posted on your findings. I’m sure someone here will be able to help you solve the problem.

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This :point_up_2:

Maybe get ERG working before you pair anything else (i.e., cadence, HR, etc…) to rule out anything weird.

Yes, I get it. It simply didn’t give me erg mode despite having it checked.

Absolutely right. Troubleshooting 101 eh?

I can’t say I understand how it works with pairing through the companion app. If I first pair the trainer without having ticked the “pair with companion app” box. Then if I tick it I am prompted to choose a power source again. Not sure if this pairing through the companion app overwrites the previous one directly to the trainer. In any case, having the trainer paired through the companion app always causes the “controllable” unit to show “No signal”.

With that said though, leaving the companion app out of the equation solves my problem. I get erg mode working like a charm then.

Thank you all for your quick responses. See you in Zwift.