Just got a power meter and got a 26 point bump; is it legit?

I’ve been using Virtual Power with a Tacx Satori for the last 6 months. I last tested my FTP on May 18th and got a 7% bump from 200 to 215. Yesterday I took delivery of a second hand Stages G2. I’ve just done an FTP test with it and I got a 21W bump. Does that seem right?

I’ve had a fairly consistent month since my last test but I doubt I’ve made any massive gains. Is it usual for Virtual Power to be significantly off the mark?

Also worth noting I bailed a bit early because the ant+ dropped out (I think I need a USB extension lead) when I was at about T-2 minues and it really threw me, so I could have probably hit another minute or two.

You can not compare power data between sources, unless you directly against each other to see what difference exists between the devices (because there is a difference in nearly every case). I don’t see that in your comments above, so I don’t think it’s appropriate to make a comparison.

When you move from Virtual Power to Real Power, you are best to ignore the old info and start with the new info. You effectively switched from one tape measure to another. And even though they both claim “watts” are the measurement, there is no guarantee that the values are comparable. There are often large differences between VP and RP measures.

Short story… ignore the old data and only watch the new data.


Chad the “different tape measure” analogy is awesome. I’m going to use that later, forget where I heard it from and probably pretend like I made it up. Thx!


LOL you are welcome to it.

Another way I have used is that it’s like comparing a real tape measure (like a real power meter) with a photo copy of a tape measure (like virtual power). They both have the same numbers and units on them, and appear to tell the same story, but the photo copied one may be scaled up or down a bit. That means that 6" on one may not match 6" on the other.

Determining which one is “right” may not be easy or even necessary. The important thing is that data from each tape measure should not be compared in most cases. The exception is that you take the time to compare the tapes with each other and understand exactly where don’t match and by how much.

That’s the reason that comparing any Virtual Power number to anything else (virtual or real) is a fool’s errand. The creation of VP is so full of potential for variation, that unless you strictly control variables between one trainer/bike/tire/pressure combo, you have no idea if it matches that from another trainer.

You can only do that with a power meter that can be transferred between each to gather comparative data. I know it seems like we should be able to do these comparisons, but the variables present lead to far too much inconsistency without taking fairly extensive steps to make it reliable.

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I saw a 12-15 W increase in FTP going from my Kickr to my Stages L. It had nothing to do with my increase in fitness.

If you’re impatient to ensure your power curve is populated by the new power meter, try:

  1. https://www.trainerroad.com/cycling/workouts/23754-h-a-a-c-power-profile-test

Along with 8-minute or 20-minute FTP test.

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Probably legit. Tacx wheel on trainers are known to be watt vampires if you calibrate it according to the Tacx utility app, I certainly found that this was the case with my Bushido which I confirmed with a mates Assioma Duos I borrowed

Article about the issue here

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Thanks @mcneese.chad. Where can I reset my power PRs?

I know there is a way, but I am having trouble finding the reference material.

Maybe @Bryce or someone else knows?

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The only way I’m aware of wipes your whole career, including TSS. Accounts -> Reset Career. You can alternatively go back through old rides with power PRs on them, and set them to exclude from the PR calculations. It’s a bit tedious, but this was what I did when I moved from virtual power to my smart trainer.

A bit easier is simply creating a new season for your new power meter, and ignoring the all time records from before.

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Yeah, i did the Career reset at one point and only discovered how bad it was for my planning after the fact. That’s why I didn’t want to make a recommendation.

The Season idea makes good sense to me considering that we don’t seem to have another option right now.


I probably will make a dedicated reference thread about Virtual Power. TR has some references:

But those don’t really cover some of the intricacies of what VP offers (and does not offer) for real use.

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So sadly we do not have a way to clear all past Personal Records without also clearing TSS history :pensive:.

That being said @gregbuk , since you only have 35 TrainerRoad workouts so far, you can simply exclude them each individually from your Personal Records. To do this:

  1. Open the workout
  2. Click the three-dot menu on the upper right
  3. Select Edit Ride
  4. Uncheck the Personal Records checkbox and save

This is a somewhat tedious process I’ll admit, but if you do want them excluded, feel free to just let me know and I’ll go through and exclude them for you.



Damn, kudos to Bryce for the concierge service…

@Nate_Pearson, give my man a raise.


Thanks for the offer Bryce. I’m not that fussed tbh. Hopefully i’ll be beating those records soon anyway, and with the power meter reporting higher than VP I’ll probably happen pretty quick.

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