Virtual Power is way off


I have sent my PowerTap pedals for an annual service and used TR’s virtual power for my latest ride. There are two options for JetFluid Pro, one with CycleOps recommended and the other with PowerTap. First of all, what is the difference between the two? Second, my results clearly show the PowerTap version is overshooting and the CycleOps is under-estimating. My HR threshold is 168-173 bpm and using the CycleOps recommended I was not able to hold anything more than 210w and my FTP is 255.

I made sure to set up my trainer as instructed in the manual and input my tire circumference which is a 23mm (2096mm), but none of the two seem to capture the power accurately.

Virtual power is just never going to be accurate. That’s why we spend all this money on power meters and smart trainers. The best that you can hope for is that it is reasonably consistent. That is it always produces about the same number for a given actual power.

If it does that, you can do your FTP test with it, and then do all your workouts with it you’ll get the right training effect. All the numbers might be 20% high or 20% low, but you’ll be (for example) doing sweet spot at 90% of your FTP, so the training will be right.

What you can’t do is what you’re trying, do your FTP test with a power meter and then try to use those numbers with virtual power.

My recommendation is do a new ramp test with virtual power, use that number until you get your pedals back, then go back to your old FTP.