Tacx Flux S sudden resistance spikes in ERG

Bugs and Support
1

I am having issues with my Tacx Flux S, where the resistance will suddenly spike during ERG workouts. It can be perfectly fine for 20-30 mins, then it will all of a sudden add a load of resistance.

Yesterday, I did a interval session where the first two sets went smoothly. I did the hard efforts as normal and dropped one gear for the easy bits. When the third set started I could barely pedal the thing during the “off” parts of the set. I had to drop to my easiest gear, but was still pushing almost 250 watts at 30 rpm :-s

Any sugegstions?

I am using an up to date Flux S (4 months old) and the latest version of Zwift on my MacBook Pro. Everything is connected through Bluetooth.

2

Is the indicated power also spiking up, or just the resistance perceived in the pedals?

3

Both are spiking. No matter how slow I pedal or how easy gear I’m in, it is almost impossible to push anything less than 200 watts, just keeping the pedals moving.

4

Both spiking potentially points to the communication link between the app (Zwift in this case) and the trainer, rather than the trainer itself.

Can you use an ANT+ dongle and try with that if you still see an issue? That would eliminate some possibilities.

5

Thanks for the suggestion. I’ll give it a shot and report back

1 Like
6

Just did a short steady session with the Ant+ USB dongle. The Flux S seems smoother with this setup than using Bluetooth. I’ll do an interval session within the next few days and will post an update.

Fingers crossed :slight_smile:

2 Likes
7

Wow, what a difference! The ANT+ connection seems so much more stable than BT. The resistance changes in my latest interval session were silky smooth, and for the first time, I was able to complete the whole set without changing gears (ERG enabled).

Thanks for the suggestion :+1:

3 Likes