Trainer Disconnects Only in Sufferfest

I ride a Kickr and connect it to my windows PC via Ant+. I have two Ant+ dongles and record in Zwift simultaneously with Sufferfest. My Kickr is on the latest firmware. All too often, the Sufferfest software just seems to stop recording my pedaling and I get drops in my cadence and power.



Any ideas why this would happen?

Do you get the same behaviour if you only have one ANT+ dongle plugged in and ZWIFT is not running?

Tbh, I’m not sure I’ve tried that. I was just looking at the Help section and it talked about interference, so I’ve ordered a 1.5m extension with 4 USB ports, so will try moving the dongles closer to the Kickr.

Echo’ing @JohnK comment.

Can you please run your next couple of workouts just running your SUF workouts without attaching to Zwift and let us know?

In the meantime - can you screenshot the double dongle setup?

  • one screenshot of the Zwift connections page once it’s up and running
  • one screenshot of the SUF connections page once the workout is up and running

FWIW - it is possible to have four apps running. One on BT, one using DIRCON (recommend that !!), with two just reading from two ANT dongles

And I have some experience of the double dongle setups myself and one thing I now try and avoid is letting Zwift have any control of anything. It’s quite ‘grabby’ in my experience.

I assume that you are using the FE-C connection for SUF and the basic PWR reading for Zwift? Is that right?

Also, are you downloading the SUFF video in order to run it. I had a similar problem starting out, and (with the minions) determined it was being caused by interference during streaming.

Tbh, I don’t know. I open up Sufferfest, let it connect to everything, then open Zwift, let it detect things and disconnect the control.

Interesting. I usually do and have had it happen just once or twice in downloaded videos, but today I didn’t and it was terrible.

I have a few things to try, thanks. Will report back with more if it’s not better (inc screenshots of connections)

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I have had the same issues between SUF and Zwift when using BT and ANT+ and it happens regardless of which is using which connection. I don’t know if this is technically true, but in my experience SUF seems to care more about correct data than a smooth connection and so if no data is received, none is recorded. Zwift seems to care more about a smooth connection experience, so, seems to have some kind of buffering going on where it hangs on to the previous data to try to smooth over small connection glitches. This may not be technically correct, but explains my experiences. I often seem one or two seconds where a sensor will stop displaying data in SUF. I almost never see that happen in Zwift - instead in Zwift I see the same HR or cadence value “stick” for a few seconds longer than it should, but rarely if ever see one of them stop displaying.

That’s interesting, but I have seen data ‘stick’ in Sufferfest for 3 or 4 seconds. Sometimes I feel like it takes me stopping pedalling for a second to make it start back up again.

Hey @AndyCr15, I’m sorry to see that you are having connection issues. If you are still stuck, please reach out to the minions here.

It is an old error. You cannot mix Ant+ and BT in Sufferfest for Windows. So either disable BT on the PC or connect all using BT only. Then in ERG mode changes in targets is spot on the second.

Interesting, thanks. I’ve turned BT off.

I did a session using the extension for the dongles and there was also no video for the workout and it went along without a hitch. There was the occasional delay in ramping up the resistance though, so I’ll see if turning off BT fixes that.

I prefer using only BT since my headset is connected using that. Though I had to buy a Wahoo Tickr heartrate to archive that