To ERG or Not to ERG?

I’m in the 2nd week of the Road Racing Interval plan. Are there compelling reasons to use, or not to use, ERG mode when doing the weekday interval workouts? In short, is one mode better than the other?


If recommend not using erg mode. First of all it makes the power very consistent which is unrealistic to the outside world. Secondly it doesn’t allow any flexibility based on how you are feeling. Such as feeling good can push the zone a bit, riding indoors you may not feel as strong so rude more at the lower end. Third during burst and full gas efforts tends to hold you back. Thirdly it’s good to train yourself to be able to push, shirt gears and not be a drone.

With that said power is power. So you’ll still get a good and proper adaptation to the training. It can be a personal preference.


I agree :100: ERG mode is lazy and flies in the face of our full gas interval prescription.

What if you are doing VO2 intervals and you set ERG mode at 310 watts but you could do 330 watts?

ERG mode messes that up but as Coach @Jake says, doing them ‘old skool’ does not.

Sometimes if I’m doing tempo work in the winter I’ll do ERG mode after I settle into the wattage I want but otherwise do your intervals by feel, full gas, the old fashioned way


Thanks guys! I really appreciate the feedback. I’ve gone back and forth over the past year trying both methods, but I honestly can’t say I prefer one or the other. However, one of the things I absolutely love is having my Fascat plan in TrainingPeaks, which means when I load Zwift, the workout of the day is already loaded and ready to go…no importing necessary.

And when you are already working out, Zwift makes it so easy to raise or lower the target wattage or to toggle ERG on/off. No excuses not to train when you make it that convenient!


A follow up question to the above…if you find there is not enough tension from the trainer and that your cadence tends to have to be super high to hit the sweet spot watts on the workouts being imported from training peaks…then would using ERG mode make more sense? I find I cannot get enough tension on the trainer to keep the watts high enough in a lot of cases unless using erg mode…I am using the wahoo kickr

You should be able to add resistance to your trainer though the wahoo app on your smart phone. You can actually as well if using a Wahoo head unit.

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Great, thank you!


Tim Brady

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I think with the Wahoo Kicker you need to do a spin up test. Check their website to see how that’s done. I borrowed a Kicker last year and remember having to do that. I bought a Tax Neo II and it doesn’t need to do that process.

so should the Field test be done with the ERG mode off?

It should be off.

I messed up and had it on. What should i do?

I put some options under your other post.

The default “trainer difficulty” setting on Zwift is set at 50% which means a 10% slope will fell like 5% in. Worth playing around with this setting to see what works best for you. Personally I have kept the default setting but use a close ratio 11-25 cassette instead. Some Zwift racers run at 30% or less to enable more consistent cadence and wattage when they hit the hills.

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After two years of consistent trainer rides (thanks pandemic!) I finally got used to erg mode as a way to ‘time trial’ my way through SST and threshold rides. I agree with the comments above with it being fake style riding, but I have to admit, my mental strength really improved, as I now can push my ftp (doing the climb plan now) for 15 min with waaaay more mental/physical strength that translates nicely to my outdoor riding.

Erg mode will now be off - it will be a transition.

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