In last weeks I’ve noticed problem with big cadence changes during racing. It’s not about problem with measurement but real rpms.
Eg. when I hit ~112rpm and change gear (2 teeths different on cassete) my rpms drops by 16-18 to around 94-96. My “cadence sweet spot” is around 105 (+/- 5rpm). Riding outdoors gear changes drop cadence by only 7-8rpms.
I’m using Tacx Neo 2T with latest firmware.
I can connect this problem with trainer difficulty changed from 80% to 20% in march but then I’ve returned to 80% but it didn’t help. Problem is on flats and hills
To me it makes sense that your RPMs would drop significantly when changing gears like that. Check out this website: BikeCalc.com - Speed at all Cadences for any Gear and Wheel
This shows that if, for example, you change from at 52x17 at 112 rpms (26.81 mph) to a 52x15, maintaining the same speed, your cadence would have to drop to somewhere between 98 and 99 rpms. At 105 rpms in the 52x15 you would be going 28.51 mph, which means you would be putting out more power as part of the gear changing process.
The speeds, of course, are all dependent on gearing, but I don’t see anywhere that a move to a sprocket 2 teeth smaller, with cadence dropping from 112 to 105, doesn’t result in an increase in speed. To remain at the same speed with that sort of gear change seems to be result in a cadence drop more like like you say you are experiencing.
112 to 105 drop i have outdoor. I ride on MTB (front 26/36, rear 11-40).
But these 16-18rpms drops i have on Zwift. For me it looks like wrong speed/resistance.
Eg. 350W uphill rpms drop to around 98 so I reduce one gear (from 14 to 16) and cadence rise to over 114. Still around 350W. If i reduce rpms to 105 I’ll NOT generate 350W…
I also have issue with cadence, did an FTP Ramp test in Tacx Trainer and when starting reaching 300 and over at 85rpm…it just drop to 30…and then zero.
Have found rider with similar issue on different forum. Recommendation is to use Firmware 0.0.34 and this…(Neo 2T has its own cadence sensor but depends on the bike the crank arm reach it more or less). https://support.garmin.com/en-US/?faq=btBijKpQyY6MQ11TybJVE9&productID=701670&searchQuery=Cadence&tab=topics
do you also have power / ressistance inacurancy in Zwift ?
Although this post is a bit old, I started experiencing this issue when switching bikes. The crank arm went from 170mm to 165mm, and the chainstay went from 410mm to 432mm. My trainer is about 2 years old and it has been working perfectly until this week when I did the switch.
I do have power meter pedals so I might use the cadence from it instead of adding the metal extension