Virtual Power V Kickr Snap V Giant Power Pro

Hey Guys keen for some advice/help and a bit of discussion…

I just bought a new bike (which has Giant Power Pro) and a Kickr Snap.

Previously to this I had been using virtual power and had an estimated FTP of 319 using TR ramp test (which i was super pumped about BTW). To my absolute dismay and horror - when I tested on the Kickr i struggled to hold 200 watts and had a new estimated FTP of 150. That is a massive difference and didn’t seem right. So I connected my Garmin 520 and had it on my bike while I did some retesting and the watts are significantly different between TR and Kickr V Giant Power Pro on my garmin.

I have tried calibrating everything and have even done the spin downs but there is such a massive difference still between my original Virtual Power to my current and between the Kickr and my Bike Power.

Does anyone have any advice or AM I TRULY AS WEAK THE KICKR SUGGESTS (insert sad face here)…

Have you done a so called “factory spindown” (advanced spindown)? That’s what I had do to on my Kickr Snap when it was new. Before that the watts was way too low, but this solved the problem for me at least.

I don’t believe so - how do I do that…?

When in the Wahoo app - tap 5 times fast on the spindown button on your smartphone and the alternative “advanced spindown” will show up.


On the turbo, are you measuring power with the turbo or the power meter?

Thanks mate I’ll give it try in the morning.

On the turbo - but using bike for cadence…

As for the normal spindown you should spin the bike around 10 minutes before you perform the advanced spindown.
Good luck!

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Ok, so are you comparing power on your new bike out on the road against power measured by your kickr? What’s the discrepancy in power between the 2?

The main thing I am trying to understand is the massive difference between my original Virtual Power FTP and my current FTP done on the Kickr - 170 watts difference.

So to satisfy my own curiosity - I connected my Garmin 520 while on the Kickr to see the difference between the Kickr and the actual power from my Power Pro and that too was anywhere from 60 - 120 watts different to what the Kickr was saying…

I understand there will be differences but these seem very extreme…

How does the virtual power compare to the giant PM? Snap’s are horrible at measuring power.

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Dc rainmaker and gp lama found the Kickr Snap to track very closely to various power meters.

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The two I had were 30-40 watts lower than my NG Eco and Virtual power…even after multiple factory spindowns, spindowns, exact same tire pressure and roller tension.

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Virtual Power is great, but must be seen for what it is. A rough estimated, based on lots of assumptions and some guesses. Meaning it can be close to real power, but it can also be wildly off.

TR makes their VP curves on each trainer model, with a particular setup. It may or may not include different tires with the related differences in rolling resistance. Tire selection and tire pressure are two huge variables in the VP calculation. Couple that with the required roller pressure against that combo, and the wheel circumference entered in the app. Then you take that soup together to get a VP Power Value.

If you pick the wrong tire circumference, set the wrong trainer, have a different tire, different tire pressure or any combo, you will get different results for VP.

Sorry to say, but you need to wave good bye to that old VP FTP. It was likely never “real” and that is OK. Presumably you used it for training to set power targets and check progress via testing. That is exactly how it’s meant to be used.

It is NOT meant to be used or compared against any other rider or power data. Doing so leads to mistakes in understanding and false expectations (as we see here). The reality of real power is often not inline with VP. Sure, we see examples where VP tracks well with some riders real power, but it seems to be the exception.

Best to make a new season starting with when you got your power meter and/or smart trainer. Ignore the old data that was most likely well overstated. Move forward with the new data you have that is more accurate and reliable than VP.

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It’s actually very close to the power pro.

What are everyone’s thoughts on the best way to test FTP on the road. 1 x 20 min effort or 2 x 8min efforts or something totally different…