Hi all. I’m new at the forum. My name is Alex from the Netherlands. I have a Kickr core, I believe V5. I bought it to train on Zwift during the pandemic. After Covid I did not use it anymore, at least not a lot. Now I want to use it again, but only with the free Wahoo app. Everything is working, except the power I have to generate is not in line with the speed. I’m pushing 250 Watt with 39-17 gear ratio and I’m traveling 23 km/hour. In zwift I was going 31 km/h at 210 Watt and a ratio of 50-17. I tried allready the spindown, different wheeldiameter settings and even the factory spindown. But when using the Wahoo app, it still stays the same problem. Hopefully someone has a solution because now I only use the lightest gear ratios.
Welcome back, @Alex1980. Most importantly, realize that indoor speed is really “speed”, and isn’t really of any great relevance.
That said, if you’re on a Kickr, and running off the Systm app, I would check your trainer setup. Make sure your wheel size and wheelbase are properly entered in the app, since those are (as I understand it), the way the app extrapolates your wattage output into “speed”.
Also make sure your trainer is physically adjusted to the right type of wheel.
If all of those are setup correctly, maybe a note to support would be the quickest way to get yourself sorted. A v5 core shouldn’t need any other sort of calibration.
The ratio of speeds doesn’t look unreasonable given the gearing if your cadence was roughly the same. I use a couple of programs with different mappings of power into (virtual) speed, and I never see such large discrepancies. I’d check the simplest things first, is your weight in kg instead of pounds in the wahoo app? Wheel diameter?
Thanks for the quick responses. I checked the setup. I tried the correct wheel diameter and also others. That was not helping. The tip on weight could be the one. Tomorrow I’ll check if it’s correct in the app, although I can’t recall that is even a parameter in de wahoo app.
It’s just strange the speed is way lower when using the wahoo app in comparison with the Zwift app at the same power. On a flat road
Actual speed on a trainer is zero. Any speed reported by apps or anything else is a virtual (made up) speed. Different apps and different devices use different methods to calculate this made up speed, and the results can differ widely between them.
Aha. That’s an explanation. I assumed the speed was a real output of the core trainer. Hopefully I can tweak something in the app, in order to use more gears. Now it feels like I’m climbing constantly.
I’ll expand a little. Virtual riding apps calculate speeds based on power, the virtual grade, and their physics model accounting for things like weight, aerodynamic drag, in some cases drafting, etc. Smart trainers can output a speed based on wheel rotations multiplied by the circumference of the wheel. They use a default circumference, but for some you can use their proprietary app to change the wheel circumference which will change their output speed in proportion. The speed a trainer reports will be quite different from what a virtual app calculates.
Helpfull information. Thank you. At the end I was not able to get it work. I “solved” it, by simply using the indoor training function of my Garmin Edge 840. With the Garmin I’m traveling 30 km/hour in gear ratio 50-18 with around 200W. That’s perfect, because now I can use the full potential of the cassette.
I found zwift speeds to be very high. Speed and hence distance travelled in SYSTM is also a little higher than I see on the road, but I think about in line with what I would see on a hypothetical perfectly flat road, race track tarmac and no wind, no stopping at junctions etc, so not unreasonable, but zwift always seemed a bit generous.