Carpathian Peak +2 & challenges related to ERG and power meter accuracy

So today I did Carpathian Peak +2 and I struggled a bit. Half way through the third u/o interval I had to drop the intensity to 94% to complete it.

I’m using an Elite Suito in ERG mode and I have a Stages PM for my outdoor rides. Both have the latest FW. Following some feedback from @jpowers in another thread I started having a closer look at the power readings of the trainer vs the Stages as the Stages seems to report higher power than the Elite trainer.

So, prior to starting my training and after warming up the Elite, I calibrated both.

During the training, I noticed that the Stages was consistently reporting significant higher power outputs. Especially at ‘higher’ wattage, the absolute difference was quite high: eg the target for the overs was 232W, however my Stages was indicating I was doing around 260W…
For the entire ride, TR (using the data from the trainer) reported an avg power of 170 - IF=0.87
My Garmin and Zwift (both using the Stages data) reported an avg power of 182 - IF=0.936…
FTP is set to the same value on all platforms.

I’ve tried to overlay the Garmin power (Stages data - purple line) on top of the TR (trainer data), aligning scales as good as possible:

So, if my stages is the most accurate and the Elite Suito becomes more inaccurate as the Wattages go up, my training intensity is quite a bit higher than prescribed, especially for the Sweetspot and Threshold work… This would mean that my sweet spot is actually work above threshold, etc… I’m thinking that recovery from those might be harder than intended. Short term, I’m thinking, hey if I can do this harder work, it’s only going to make me stronger, but I’m not sure longer term how this would play out as I understand that recovery would be quite a bit harder etc. Is this going to be a problem?
This might also explain why I struggled so much doing today’s workout as all intervals appeared to be above FTP vs under/over FTP.

Alternatively, my Stages is off and the Elite is the most accurate. In that case I’ll just ignore the Stages data altogether for my indoor training. Not sure how I should go about the data from my outdoor rides then…

Does anyone have the Elite Suito and Stages and have you observed similar challenges? How did you deal with those?

Or it is perhaps time to contact Elite and Stages support to have a look at the data?

Keep your indoor and outdoor FTPs separate. You’ve got different power meters as well as different amounts of cooling. Ignore that stages PM when you’re indoors.

Just make sure that you are calculating the TSS with the proper FTP for each workout.

If you do happen to contact either of the manufacturers and find out one of them is faulty, please pass along the info. I know 5 people that bought Elite Diretos and they have all been replaced at least once under warrantee. (2 of them twice) I was hoping that the Suito would be better. We are looking at changing from Saris to Elite at the shop I work at because everyone is buying Elite at another shop across town due to the price difference, but we’re wary due to the reputation of the Direto.

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@britter440 - I’ll let you know what Elite comes back with. I had to do a test and send them the output from the Elite and my power meter so they can compare.

Today, I did Mary Austin-1… here is the analysis - one from the Elite Suito data, the other from my Stages PM…

Elite Suito:

Stages:

While I’m trying to ignore the Stages PM when training indoors, just notice the difference in avg power and XSS/Strain score!
My Garmin using the Stages recorded this is as a VO2Max workout vs a Threshold one…
My Garmin reported an IF of .936 vs the targeted 0,89

Am I overtraining like this? I mean training this close to FTP and then having this difference making these trainings actually a lot more intense… will this backfire? Should I look at dropping the intensity of the Elite Suito to be more in line with what it should be as per my Stages PM? Or should I just ignore the Stages PM and hopefully reap the benefits of the trainings actually being a bit harder?

Note: I don’t mind working hard at all - problem is that with whatever sport I do, I tend to go hard and this has resulted in overtraining and injuries in the past, which I’d like to avoid…

If you do your FTP test with the Elite Suito and you do your workouts with the Elite Suito, you should be fine.

It looks, very roughly, like your Stages is about 4-5% higher than the Suito. That’s within reason, since they’re measuring on opposite sides of the drivetrain. If it’s reading 5% higher, then the IF will be 5% higher and the TSS will be about 10% higher. But you should be using the values from the power-measuring device that you calibrated (tested FTP) with.

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There is a reason Trainerroad advocates doing a new FTP test when you change a power meter.
So use the same PM in training that you use to test with. If you want things to be somewhat consistent between indoor and outdoor, use Powermatch and get the power from your Stages.

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Im in a similar position with my Kickr Snap and looking to get a stages to perform outdoor workouts. I know my Snap reads lower.

However RE the training: if you perform the FTP test using your trainer then the FTP, whilst maybe incorrect, will ensure the workout targets are correct for the required adaptations. I.E you’re still working at the correct % of your FTP.

If you want to ensure you’re outdoor workouts are set correctly then im guessing you need to use your stages and power match. Then perform a new ftp test to set the correct FTP for indoor and outdoor workouts.

Is your stages single sided?

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What software is that? Carbs and fat data is interesting!

Yes this.

Right off the bat the 2 different devices are measuring power at different points, one’s at the crank, the other’s at the wheel. You’re gonna have drive train loss which accounts for part, there’s going to be a general difference in how they’re measured, and plenty of factors with pedal stroke / cadence / power smoothing / single sided vs dual sided when you’re in erg mode.

Just use powermatch and none of this matters as long as you tie your ftp to your stages power meter, which you should be doing anyway since that’s what you’ll use outside.

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@alexgold123 - Xert - https://www.xertonline.com/

Since you mentioned powermatch, I’ve started using that. I guess that sort of levels out any differences. Thanks!