Easier going uphill in ERG mode,harder downhill

Yeah, the power in ERG mode is consistent for me regardless of hills. Whether you do your ERG workouts on tempus or the alpe (up or down it) you’ll get the same workout in ERG mode by design. I have data from many workouts on various courses that show this consistently.

Edit: In fact, on my longer Z2 workouts I often go up the alpe, then back down, then back up again, and the power profile is completely consistent as expected.

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Does the power on screen change? Try doing it not looking at the screen and see if you can guess when you’re going up or down hill

Edit actually this is crazily off topic so maybe someone can split it in to its own thread or we should stop this particular tangent

It’s probably something in the region of 10% going by feel. I can be sitting quite happily at 250w for 10 minutes in a workout block and then when the road on screen goes downhill the resistance increases, while the power supposedly remains the same.

I can do the same workout in PerfPRO Studio and this doesn’t occur at all, only in Zwift.

But as you can see they’ve already determined it is in our heads only. And it’s the same enormous frustration each time this is raised.

This is why I avoid workout modes. If Zwift pulls out analytics on my usage of their app (assuming they have it) workout modes are probably 5% of my use for this reason.

Workouts for me are probably about 90% of my zwifting, I’ve mentioned it before and just been told it’s flat gradient in erg

In a banded group workout you can actually see your position in the pack change, granted I’m sure some users won’t be in erg mode, the steady w/kg figures while I surge back and forth suggests some are. Again that could be different trainer reporting or smoothing and a few other things which are hard to eliminate

It’s been especially noticeable on the spring rides which are mainly sweet spot, so not overly stressful on the legs and you are spent after 10 mins when you hit a descent

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I feel like it’s the opposite, like erg resistance is higher going uphill and lower going downhill. But if I ignore the main screen and only look at companion I don’t notice it at all.

Maybe if you posted some data with an ERG workout alongside the elevation profile that showed this phenomena it would help.

I’m happy to do that for any of my workouts that were on varying terrain. There’s never any change of resistance across profiles in ERG mode for me.

Remember that people of different weights will react differently to the gradients. So in a banded group ride it’s still expected to see people swap positions.

I don’t have separate power meter pedals so how would I do that? Am I supposed to spend AUD$1000 on power meter pedals to prove a problem?

Of course Zwift would say no change but that’s the problem because we can see people complaining about this and that puts the numbers from Zwift into question.

Interrogation over. I’m out. :roll_eyes:

Wait, so you’re saying that Zwift is showing the wrong wattage on hills? Is that your claim?

You can read what has been said already, I’m not going to repeat myself.

Right now there is 0 evidence that it’s easier going uphill in ERG mode. If you provide some then that would be new information.

Well if someone gives me $1000 I’ll go buy power pedals and test it to show the differences between what Zwift has on screen and what the power meter pedals show. But I’m not going to do that.

What of the others, are you going to interrogate them too?

But why does this only occur when the gradient changes? When the gradient remains the same there is no change.

Plenty of people have said this, over to Zwift to do in depth testing to check it, rather than the defenders of Zwift shouting it down.

Why do you need power pedals to show this? The only reason is if you think the fit files are wrong, correct? The fit files will show the power your trainer exposes which is all you would need to test inclines vs. flats etc.

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Trying to think through how this could be tested without access to the resistance data being sent to the trainer.
You’d need to see power, cadence, and gradient. I don’t believe trainer resistance can be directly shown on a fit file.
In erg mode, resistance should be inversely proportional to resistance. If gradient was impacting resistance in erg mode, then this cadence-resistance relationship would change depending on the gradient.
Power should be essentially fixed for an erg mode workout, so you’d want to see a ride with on a route with varying gradient, a steady power workout, and ridden with steady cadence. Then have the rider note whether they’re feeling any resistance change, and whether it lines up with gradient changes.

Why is cadence needed? If the power is consistent across gradient then isn’t that all we need to know?

If you go back to the maths, power is equal to torque x angular velocity. Angular velocity is cadence, and torque is felt as resistance. The theory is that gradient is also impacting resistance. So you want to have data for as many of these variables as possible.

I don’t think you’d find anything, because I think it’s most likely the rider is subconsciously changing their cadence when they see a gradient change, which is driving the resistance change.

Cadence as close to level as I can get it:

I’m not a robopacer but I kept between 81rpm and 85rpm, average power 248 watts with average heart rate 158bpm which is not near my 195bpm maximum.

I do not have power smoothing enabled on my Kickr Bike.

Whenever the gradient changes downwards the RPE increases, when the gradient goes up the RPE for same power feels easier and when the gradient is flat everything remains steady with no changes on RPE. This is how it should be.

In other apps like PerfPro studio there is no gradient logged at all and there shouldn’t be - it’s irrelevant for ERG mode. As an example from another application in ERG mode:

2x18min at 70rpm cadence at 270w (4.6w/kg):

No elevation recorded and the RPE got progressively harder near the end of the 18 minute block (normal), but not increasing or decreasing in the middle of the block.

Totally agree with my colleague, on downhills the torque increases and the cadence tends to fall while maintaining the same watts in the ERG, in the hard intervals that increase in torque can even lead you to not complete the interval. I try to do the hard intervals uphill, but if I run out of climbs and the descent begins, I prepare by increasing the cadence so that this increase in torque does not affect the muscles.
All the best

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That’s exactly how ERG mode works - trainer maintaining the same Watts, independent of cadence and torque (which are determined by user).

But the effort shouldn’t vary by the gradient, which is what does happen - the effort increases and reduces depending on the gradient, no matter that the watts and cadence is kept the same.

Enough people have reported it that it isn’t just the imagination of one person.

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