ERG mode, short for Ergometer, is when your smart trainer automatically set the resistance for you. A smart bike trainer and a compatible cycling app or bike computer are required to use ERG mode.
When riding in ERG mode, you are basically telling your trainer and cycling app to take control adjusting the resistance for you while you concentrate on your workout. Smart trainers will make small adjustments to reach the target power that you set either manually with your bike computer or with a structured workout.
When in ERG mode, your trainer will try to keep you at a specified power wattage goal regardless of your speed or cadence RPM. Let’s say you want to ride at 200 watts. You set your gear and start pedaling at 100 rpm. The trainer will adjust the resistance to keep you at 200 watts. If you decrease your cadence to 80 rpm, without adjusting resistance, your watts will drop. But in ERG mode, your trainer will make tiny adjustments until you are back to 200 watts.
Naturally, as you ride longer intervals, your cadence will vary. You might start the interval at 100rpm, then a few minutes later, you might settle around 85 rpm. Your smart trainer will make adjustments as you change your cadence to keep you at your target power.
Typically, it takes few seconds or even milliseconds for the trainer to sense changes and make tiny adjustments to keep you at your target watts. Some trainers are better and faster in making these adjustments than others. I’ve covered that in my ERG Mode Showdown article.
HOW TO RIDE IN ERG MODE
When in ERG mode, I typically like to select a gear that I like. I try to change the selection from ride to ride to minimize ware and tare on my drivetrain and no cross chaining.
Riding in ERG mode can be a little challenging since the trainer will make every effort to keep you at your target power. When entering an interval, you want to be ready to increase your power. You will feel the increase in resistance until you reach your target power. Make sure your cadence is smooth and at your goal rpm. No need to change gear. Just sit tight, and keep pedaling and you will see your power reach that target line. If you want a lower rpm at a selected power, simply lower your rpm. The trainer will make the necessary adjustments to keep you at your target watts. If you want a higher cadence, simply increase your cadence and the trainer will adjust.
Some trainers will broadcast your target power rather than your actual power. So if your target power is 200 watts, you will see 200 watts on the screen. However, if your trainer is broadcasting your real power, you will notice a slight variation in power numbers. It will slightly go up and down your target power. However, overall the power line should be smooth and your average for the interval should match or come very close to your target power.
Here is graph from a ride in ERG mode. Notice how the power line is very smooth:
Here is the same ride but without using ERG mode. You will notice how there is a lot more variation in power:
When existing an interval, don’t expect the trainer to just let go of resistance. Keep pedaling and the trainer will slightly release tension.
AVOID THE DEATH ZONE
In ERG mode, your smart trainer goal is to keep you at the specified target power. If you set it at 80% of FTP, then it will do everything it can to keep you at 80%. For the trainer to do that, two things need to happen. Resistance which comes from the trainer, and cadence, which originates from the rider. If you start lowering your cadence, the trainer will attempt to increase that tension. In some cases, where you might be having a bad day, you realize you can’t keep that power and your cadence will start dropping. Unfortunately for you, your smart trainer doesn’t care you are having a bad day and will just keep increasing the tension. If you can’t keep up with the increase in tension, you will find yourself at what I call, the death zone where you can’t pedal anymore and the trainer will basically put the clamps on.
With most cycling apps, the app will realize what’s going on and will disengage ERG mode so you can start pedaling again.
Most apps will allow you to adjust your workout. So if you are having a good day and you think you can beat your workout, you can increase or decrease your target by a certain percentage.
HOW TO ENABLE ERG MODE
ERG mode can be engaged by either using your bike computer such as Garmin Edge or Wahoo ELEMNT. Or by using a cycling software like TrainerRoad or Zwift.
In Zwift, when selecting a workout, toggle the ERG mode on or off in the workout select screen.
You will also have the following controls on the Zwift Link Mobile app
In TrainerRoad, you can select ERG mode from the menu at the bottom of the workout screen.
In Garmin Edge or ELEMNT Bolt, you can either select a specific workout or just simply select your target watts and the trainer will attempt to keep you there.
Make sure your trainer is paired with your bike computer. On your Garmin Edge, under setting, go to Trainer and you will see the below menu. Go to set target power, and you will have the ability to set your target watts.
You should see your target watts on the screen. You can quickly change that by just pressing the top right button (menu) and it will take you back to the Target Power screen where you can increase or decrease youe watts. Press the menu button again it will bring you back to your workout screen.
The Wahoo ELEMNT bike computer can only control Wahoo KICKR or Snap smart trainers. Support for other smart trainers should be available on their Elelemts bike computers later this year via a software update. Once your KICKR is paired to your app or bike computer, you will have the ability to manually control your target watts.
SHOULD YOU USE ERG MODE?
This can be a hot topic depending on who you talk to. Some athletes like to have full control of their workouts, some others will argue that ERG mode doesn’t mimic outdoor riding as the rider determines the power output by utilizing the gearing selection and cadence to generate power.
In my personal experience, it doesn’t really matter. If you can hold 200 watts indoor for 3 hours, then you should be able to hold the same watts outdoors. To me, the question comes down to, which workouts are good with ERG mode and which workouts aren’t good.
For ERG mode to properly kick in, you need to give it around 30 seconds. That’s usually the time it take most trainers to adjust and stabilize resistance. So I usually avoid ERG mode with intervals that are less than 1-minute in length. Usually Vo2 max or sprints, I like to disable ERG mode.
I also like to avoid ERG mode with workouts that are above 95% of FTP. So if I am doing a 2×20 at FTP, I like to build into my target power rather than jump right to it.
Tempo and Sweetspot intervals are perfect workouts for ERG mode and can make these workouts mentally challenging.
However, every athlete is different, so I would encourage you to give it a try and see if you like it.