ERG Issues - anyone else ever get this

I guess it is frustrating that this is seemingly a common issue that has been allowed to persist.
It’s one thing when you are in base and the intervals are such that 1min even 20% over target won’t break you because you are in sweet spot and it just makes the interval more like a FTP set. What’s bad is when they are VO2max and meant at prescribed to put you on the limit and then you get a “race winner” kick to start things off.
I don’t want to have to drop the workout intensity as it seems a shoddy workaround that messes up a lot of additional things. @Nate_Pearson is this issue a known one, and is there a plan to address?

if you pull up Fang Mountain +3 and look at all rides, yours is the only one I could find looking at last 100 (going back over a month ago).

So then I pulled up your calendar and I’m seeing the overshoot issue on rides going back to March 1. Didn’t look any farther.

Pulled up Hunter and looked at 100 workouts going back 3 days, and yours was the only one with obvious overshoot.

Have you done an advanced spindown on the Kickr? I’ve got a 2017 Kickr direct-drive and since Oct 2017 its gone wacky on me a handful of times and required an advanced spindown.

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The root issue is that the slope of your two power meters do not match.

What we can do is be more responsive and save offsets between the two power meters between rides. This is in internal testing now.

It’s looking good and I’d like to get this out to a closed beta this week. Join this thread and we’ll start enabling the role for people as soon as it’s ready. Note: It will be mac/pc only at first.

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So save the offset between the trainer and the power meter at different wattages?

I noticed issues last night with my kickr 2018 (wheel off) and my pioneer full left right power meter last night where it seemed like some of the intervals were good but on some my power meter was reading at least 10 watts higher. Did a factory spin down after workout so will see if it’s still an issue during the next workout. So not sure it’s not because I’m doing something wrong, just bring it up cause it seems similar to this problem

It’s not as simple as that. I wish it was!

Question, if it is an offset issue between the two power meters issue does the gearing impact the slope? For the power meter I would assume not but I mean for the trainer. If I’m in the big ring on my kickr going at x watts the flywheel is going to be going at a much different speed then putting out the same watts in the small ring. Since speed of the fly wheel is what the kickr uses to calculate wattage it would seem like it could calculate a different wattage between the two rings. That means the slope is different between the two rings causing power match to screw up. Not sure if that is right or not

I’ve done ANOTHER advanced factory calibration of the KICKR, so we’ll see if it makes any difference tomorrow during Baird+6

:+1:t3: Good luck!!!

I’m on the TR open beta and don’t see more than a brief high with my current trainer, but it used to be a problem with a different trainer, so I switched Power Match from auto to manual, which I’d adjust between sets until it was near perfect. Once you’ve done a few sessions it’s actually quite easy as you learn an approximate divergence at the interval & only need to tweak it. I’d reliably be off by 1W for last few intervals. The rests would always be way off though. The problem is the discrepancy between trainer and power meter is hugely different at rest and during intervals so it has to change loads during the first few seconds of the interval.

How did you enable this? i am on “early access” but dont see anything there.

Didn’t do anything. Just mentioned it as I don’t see this problem after a few seconds (in case it is something improved already). My guess is that it is more related to the trainer and people should just switch to manual powermatch until it is sorted In the software for everyone.

I suspect what they’ll end up doing is remembering an offset for high and an offset for low, just like I did once, but automatically in the software so it can be changed easily.

The evolution of my ride this morning following advanced factory calibration

Issues pairing…warm up sucks target missing…this should be fun…first intervals OK this isn’t too bad
image

THEN…

I think I’m going to smash something

Target of 355, throwing the watt bombs down of 460+
Absolutely ruins the workout.

I knocked things back a few % from there to try and compensate for these overshoots but man its a joke trying to do anything when this is what is going on

I don’t know. We would like you to not shift gears in ERG mode. That’s a guaranteed way to have a bad experience.

I guess I don’t need to do it in sweet spot but when using sufferfest and others where there was a short interval with a large change in resistance I changed the front gear to help the trainer catch up faster. Though guess if you set the kickr to report speed based on wattage you’d have no idea the speed of the flywheel so could only work with that option not enabled.

Or pair to di2 and know what gear someone is in but not that many people have di2 so guessing that wouldn’t be used by many people.

Amazing! I’ve just been living with this thinking it was just the nature of the beast. All my under-overs become over-under-overs. I just tell myself it’s extra training, but man it can be crushing on the last couple sets.

@RONDAL you appear to be attacking the intervals. Have a look at your cadence in the workouts you attached. You may be doing this subconsciously (I know I do with VO2 stuff as well); you will see you cadence increases as the interval kicks in.

ERG/Powermatch is basically a feedback loop, adjusting to changing variables. It will always work best when you change only a single variable. You are changing both the power (interval) and the cadence at the same time - this will always generate what you are demonstrating. You also drop your cadence before the end of the interval which causes the power to fall away at the end.

Don’t take this the wrong way; but in your second chart it looks like you are struggling with the workload. You charge into the interval (causing the spike) and then your cadence fails before the end (causing the power drop). We’ve all been here :slight_smile:

In a perfect world your cadence line should be as flat as possible - this will produce the best ERG experience and will work best with Powermatch as well. If you want to increase cadence before an interval do it before the power change starts; then keep it consistent throughout the entire interval.

Flatten your cadence line and I’m sure you’ll have a much smoother experience. Hope that helps!

if anything i allowed my cadence to drop when the load kicked in, still got a big spike at the beginning of each interval

I hear you, but it doesnt seem to matter. The swings happen if flat, dropped, slight increase in pace.
The fact my 2014 KICKR reads ~26% high doesn’t help. I did a 20min FTP validation test last week after my ramp test and had my garmin running to pick up the KICKR power just so i could see how bad the offset was.

This is the result;
4iiii: 20min avg = 291w, 291 NP

KICKR: 20min avg = 367, NP 373w

So yeah I can use my KICKR, but the readings are garbage.

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I hear you on the KICKR mine is the same. I’ve turned off power smoothing through the Wahoo app; and also set the trainer to use an ANT+ power source - I’m using my Quarq to be used by the KICKR to manage power. You might want to check power smoothing is off, and also try having your 4iii’s be a power source for the KICKR? Also pretty certain that if you really focus on keeping your cadence within a very narrow band the effect will be minimised.

There will always be a bump at the start; just the time delay in the KICKR increasing power, the 4iii’s reporting the increase, the software responding to the increase etc; then the system realising your too high, and bringing down the power etc etc. This endless loop will create a bullwhip effect especially if the cadence changes.

Our engineer looked at this one. It looks like your trainer or power meter has a ton of drift during the workout, and that’s making it hard for PowerMatch. The difference between the two starts off very high, then gets close and close for each set.

We don’t know if it’s the power meter or trainer that’s drifting.

This was helpful, it’s given us some ideas on how to respond more quickly, so thanks for sharing!

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