ECB iOS App + Wahoo Kickr 5th Gen = ~5 secs delay

When using the ECB app with my trainer (Wahoo Kickr), I’ve been noticing a delay between when the interval starts and when the resistance gets adjusted. The net result is that I end up working less time per interval, and all the SMART intervals are always at a higher power, to compensate for the lag in the start.

Is there anything that can be done about this?..TrainerRoad, for instance increases resistance 3 seconds before the interval starts.


Which workout is this? And are you power-matching using a dedicated power meter?

Adding a offset is something we’ve previously considered for the app. It would be best to determine what the offset should be & set it automatically, since each trainer brand & model is a bit different.

SMART - I Won’t Back Down

But in general, I notice the delay in every workout.

I don’t know what power matching is in this context…could you explain?. I’m just connecting my trainer Wahoo Kickr 5th gen (powermeter and power control) to the Xert Iphone App normally via Bluetooth. Workout mode set on Auto. No other device or app is involved.

Power Matching is enabled automatically if you pair your bike power meter. Means your power meter controls the trainer so indoor/outdoor rides are in sync in terms of measured power.
A SMART dynamic power interval is supposed to work that way to ensure you meet the individualized strain goal.
Advanced Workout Design using SMART Intervals – Xert (

Your generated power graph looks normal to me.
Transition response time is a function of the trainer. Some brands offer an option to adjust sensitivity through the trainer’s native app. Same issue applies on either end of the interval (start/end) so net effect should be a wash. Starts a little late, ends a little late.

Related – Very short intervals and ERG? - General - Xert Community Forum (

Except that while the trainer is adjusting you are not able to achieve the target power. Hence, the net result is less power at the target duration.

Post your actual activity chart for that workout like I did with Target Power enabled.

Here it is

On my Kickr Bike, all the intervals end up shorter than what’s prescribed by Xert. It doesn’t really make much of a difference for intervals 45 seconds or longer, but it makes a big difference for the short intervals. I don’t use erg anymore anyway, just ride Zwift, for other reason…It’s a lot more fun.