Hi everyone. This will be a bit long winded so bear with me please…
I’m an experienced triathlete and cyclist and have been competing for quite a few years now.
When we went into lock down due to the pandemic I got a Tacx Vortex wheel on trainer off a mate of mine to use on Zwift as we couldn’t get outside on the bikes. I’ve more or less ridden it every day and have seen massive improvements in power. For reference I kept the Tacx Vortex calibrated to within an inch of its life…Tyre pressure and roller pressure exactly the same, every ride without question. Re calibrated it regularly etc etc. I’m very strict about things being accurate!
I’ve just bought a Wahoo Kickr Core (brand new) last week. Calibrated it before riding it and I’ve seen an instant increase in my power when racing. I thought something isn’t correct here!!! So I did the ‘factory spin down’ and I am having the same results. I am putting out power “easier” on the Wahoo then I did on the wheel on trainer. I’ve been told in the history of the world no one has every switched from wheel on to direct trainer and see a power increase.
All I can put it down to is the Kickr has a big freewheel which helps the pedal stroke and is just a better, smoother piece of kit to use. Where as the Tacx was a pig to ride at anything above 270 watts.
I had the same happen to me.
I went from a wheel-on trainer, Bkool, to a Wahoo Kickr.
My power increased too.
I had a suspicion that the Bkool wasn‘t accurate, so I wasn‘t supprised to see an increase in power.
I went from a wheel on dumb trainer with a speed/cadence sensor to the Kickr Core and saw a large increase in power as well. I attributed it to having an actual, accurate power meter in the Kickr (+/- 2%) versus an estimation with the speed/cadence sensor.
Yeah I would agree. Lower watts see a little harder to maintain but pushing above 300w is not as hard as with a wheel on. I think it has to be down to the freewheel?
What is the difference in power that we are talking about?
You could just assume that the higher power reading must be correct
There is also a more thorough calibration of the Kickr that you could try, this is called the Advanced Factory Spindown.
Also, with your experience, you should be able to judge by the speed that you can maintain outside which one of the power readings is more reasonable.
I had the exact same problem. I have used for many years a rear wheel power tap g3 power meter either outside or indoor on a dumb wheel based trainer on Zwift or on my garmin. The watts from these two match each other and with my RPE.
Just bought a kicker core and on Zwift the numbers are way too high. Say 250 watts with modest effort. Also if I pedal in my hardest gear 50 x 11 I spin out at only about 320 watts. I should be able to generate over 500 watts.
Like this training is difficult because I don’t believe the numbers and I just can’t work as hard as would like to. Any help would be appreciated.
For whatever it’s worth, I have a Kickr Core that I suspect may be reading power slightly too high also. I dual recorded during an FTP test on Sufferfest against a Quarq power meter. I believe the Kickr was estimating 2-4 percentage points higher than the Quarq for my 5s, 1 min, 5 min, and 20 min power. I have another FTP test against a left-only Pioneer power meter, and the Core was higher by about 5-7 percentage points. Take this one with a grain of salt because it’s left-only, but it does corroborate the Quarq’s readings.
Do note that you do expect a trainer to read maybe 1-2 percentage points lower than power estimated at the pedals or chainrings because of drivetrain losses, more so if your drivetrain is dirty. My situation is the reverse, in that my crank power meters are reading a bit lower. Now, my drivetrain is very clean, and in fact I’m waxing my chain. I think the wax proponents have it right, but they’ve never said that waxing can violate the law of conservation of energy.
Now, what to do about it is the question. I don’t see anything that we can actually do apart from make sure the firmware is updated and do the spindown calibration regularly. I suppose I could take my recordings to Wahoo and ask for a new unit, but the Quarq is close enough to the Wahoo reading that they could say that both units being within the manufacturer stated accuracy.
My riding friend has a kicker and I suspect it is reading pretty high as well. His zwift workouts routinely read over 240 average power for 1.5 or 2 hours. Just stating facts but I’m a faster rider than him and I struggle to have avg numbers around 180 I know I’m not powerful🌝.
Hi. I compared a lot the numbers of kick’r core against 4iiii dual side and later against a quarq dzero, and in both case they read 7 to 10% lower than the kickr. So I have no faith in wahoo!
