The tacx concept of “Virtual speed”

I have another interesting quirk to discuss with you relating to my Tacx Flow turbo, or indeed any other Tacx turbo that has a relatively low maximum slope simulation capability (i.e. other than the Neo, i-Genius or Bushido) such as the Flow at 6% max or the Vortex at 7% max. This is from the Tacx support pages

“When a trainer cannot apply enough resistance, the measured speed does not comply with your exercise (training program) anymore.
To solve this the speed is calculated (Virtual Speed) based on the power you are producing and the exercise data (current slope).

“e.g. You are riding an exercise which consists of a single 10 % slope on a trainer which can only apply enough resistance to simulate a 7 % slope.

“Using measured speed you will finish the exercise much sooner compared to actually riding the same 10 % slope in real life, because the trainer cannot apply enough resistance causing you to go faster resulting in the exercise costing you less effort.

“Using virtual speed your exercise will be much closer to actually riding the same 10 % slope in real life, because it calculates how fast you would be going on a 10 % slope based on the effort (power) you are producing on the trainer

“Keep in mind speed shown in TCA is also NOT the raw speed from the trainer. It’s always calculated with the same virtual speed calculations but not flagged as virtual speed cause it’s less than 10% deviation from the RAW speed of the trainer.

“Measured speed from a sensor is treated as raw speed.”

So if you use a speed/cadence sensor with your turbo bike, you will get raw speed recorded, allegedly. I have certainly noticed downhill speeds being greater then I would have thought, and uphill speeds possibly slower (but then that may be my issue!)

On the retailer Wiggle’s site I see it asserted that apparently Zwift have partnered with Strava to allow virtual rides to count towards Challenges if you use such a sensor (as I am only riding turbo at the moment, I have zero distance and elevation in Strava Challenges for January, and probably December too). My personal targets are as normal. See:

Never mind the potholes on a real road; on a turbo, it’s a minefield out there!

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