Drifting power while displayed power is correct

Hey all,

Here’s an interesting one, first off the set up:

Apple TV 4K
2020 Elite Drivo
Wahoo Bolt
Giant PM Gen 2

Yesterday’s workout I had the following set up to determine power accuracy between the power meter on my bike and the Drivo Trainer.

Drivo Trainer paired to Zwift
Power Meter paired to Wahoo

Started my workout that was imported via Training Peaks to Zwift. The workout was a 3x20min. Everything was tracking really well between Zwift readings and the power meter on the bike until my second interval. I felt the resistance ease off from the trainer, yet the power displayed on Zwift was staying the same (290w). When I looked at the power reading from the bike it was reading at 270w. During the next test interval and final set everything seemed to correct itself once again.

When I compared the two files it was evident the smart trainer hooked up to Zwift drifted power dramatically during that interval, even though power displayed correctly on Zwift.

I hope that all makes sense, my questions are if anyone else has experienced this. And perhaps opinions if this is a Zwift issue of a trainer issue?


HI Dino, welcome to the Zwift forum.

There are some trainers that will broadcast the power value required by the workout when in ERG and not the true power output during the workout.

Something like Zwift tell the trainer hold 290w then the trainer try to hole 290 but it is hard with the rider applying different power on every pedal stroke so instead of sending the variable power the trainer send the 290w number back to zwift.

That is why some trainers has thes nice smooth graph in ERG mode. but in reality the power fluctuated between 280w and 300w

DCrainmaker does good trainer reviews see if he has done for this trainer.

Thanks for the reply Gerrie,

I understand the power fluctuations based on pedal smithing and simply holding a certain number, this is different though, power drifted lower as the interval went along. Started at 290 and ended around 270, avg 276w.

DC and GP Lama gave great reviews on the new Drivo, super accurate (+- 0.5). And true to that. Nothing was said about drifting. This one has me stumped. If I can I’ll try and attached pictures showing the graphs.

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Here are the graphs, compare the second 20min interval. You will see the drift trending down in power.