Android-Zwift drops out-Is it possible to pause/stop a ride and resume?

Last winter (2019-20) I had occasional issues with dropouts while riding in Zwift.
This winter (2020-21) the dropouts are a regular occurrence and are driving me mad.

Equipment- Tacx Flux 2 trainer, either Samsung Galaxy S5e tab or S7 tab (will happen with either tablet).

What is the problem- During rides (not workouts) suddenly my power output will read “—” and my avatar just slows down to a stop.

What has been tried to fix this- 1) When this happens I have tried to back out to the menu and re-pair the trainer. The trainer is paired up, and even if I re-pair it Zwift responds with “No Signal”
2) BLE dongle with USB cable to get sensor closer to trainer.
3) New tablet (S7)
4) New Wi-fi router. I now have excessive bandwidth and signal strength available in my pain cave.

So none of this has fixed the dropout problem. The only solution I have found is to close the Zwift app and restart it, but if I do that I have to start my ride over.

So this is the question: I have seen that the companion app has a stop button when it is paired and you are riding. Can I use this to stop the ride, close Zwift, restart Zwift, then resume my ride from where I was when the dropout happened? If not, why not? This would be basic programming to provide such a feature. I am not the only subscriber who deals with this problem. A viable solution for this problem needs to be added to Zwift for all platforms!

You seem to be using BLE.

I had similar issues - on a Windows laptop. Strange, as you are using an Android tablet…

My “solution” is to power-cycle the trainer (I have no reason to suspect it, but as it “solves” the issue, I keep using this method)

I wouldn’t recommend exiting the ride as you describe as I think Zwift will consider it “finished”, and will not resume it.(never tried this ZC button… too scary)

I wonder if your Bluetooth connection would be restored if you wait for 20 seconds.
There was an article about it (fairly technical)

https://blog.classycode.com/a-short-story-about-android-ble-connection-timeouts-and-gatt-internal-errors-fa89e3f6a456

It boils down to the way how BT connection is coded in Android: if your Tacx trainer did not close a BT connection correctly after transmitting the next data packet, your tablet would wait for 20 seconds before attempting to reconnect.

I think it may be worth testing. Just wait and see if connection gets restored after 20 seconds.

If it will get restored, it probably will not be Tacx fault. I would guess, it is not that the trainer did not close the connection, but one of the data packets got lost, possibly due to interference with other radio frequency signals in your home, maybe open BT connections on your other devices or even on the same tablet (if you listen to music using BT headset). A possible cause of action is to try ANT+, if android supports it (I think I read it does support ANT+ protocol natively (don’t take my word for it, though), in which case you might only need a new dongle). Some people find a significantly better stability with BT in their home, others write in forums that a switch to ANT+ solved their problems. For me, ANT+ definitely works better.

Wahoo fitness, which makes heart rate monitors which can talk on two BT channels to two devices, actually advises against using this feature to avoid interference.

Very nicely written.

There is still the minor question of why it got disconnected in the first place… “interference” is used way to much in the context of Zwift issues.

BLE is designed to be able to withstand considerable interference in the presence of other ISM entities. Even ANT+ has (rudimentary…) provisions for addressing interferences.

Do you have your BLE earphones similarly disconnect? Any other BLE device you may use?

Indeed, ANT+ in Zwift seems to have less issues, so if a workaround is sought for, this might be it.

At the same time, there is no reason BLE on Zwift will be problematic - and Zwift need to address this.

As I expected people start suggesting that I should try ANT+. That is not going to solve the problem. I have chosen to use BLE as if you do your homework on wireless protocols you will find out that BLE is a better option than ANT+.

I have given up on the hope that I can eliminate or solve the dropout issue. I live alone, and I do not own any bluetooth speakers, headphones, or smart home IOT items that could be causing interference. I believe that the only real fix for this would be if Zwift were to switch to cloud based computing for the game.

So my question still stands: can I use the companion app to stop a ride during the ride, restart Zwift to reconnect my trainer and then resume the ride?

No, the Zwift app has no way to put you back to where you were riding before you restarted the app.

You don’t mention power-cycling the trainer. When the problem happens and you attempt to repair it via the Zwift Pairing screen, have you tried rebooting the trainer to see if that lets it connect?

Yes, multiple times I have power cycled the trainer when there has been a dropout in an attempt to restore the connection. So far the only fix is to close Zwift - it seems once it breaks connection to the trainer, even if the trainer is paired up, Zwift cannot continue with the ride that was underway, I just get “No Signal”. This happens on both of my tablets.

I have come to believe that the connection between my tablet and the trainer is not the issue here. I believe that Zwift will experience hiccups that result in a broken connection to the trainer that cannot be overcome without closing Zwift and restarting.

Zwift, you really need to fix your app and build in a way to continue a ride that is in progress in case of this type of dropout.

Ok, I thought you might have tried that but I wanted to check for sure.

It does sound like the Zwift connection is broken and you need to restart the app, as you say. Which isn’t great.

Have you raised this with Zwift support?

“Homework” and theory of how different communications work mean absolutely nothing if practical experience proves otherwise. I have BT and ANT+ dongles plugged in into the same extension hub, both are at exactly the same distance from the trainer, and ANT+ always works much better. Which is why I always use ANT+. BT tends to be a struggle most of the times, with unstable and lost connections and everything. I do not know what the reason is, perhaps ANT+ reconnects much faster. I am not alone, if you scroll through the list of topics in this forum, there are many more posts about BT connection losses than ANT+ connection losses. But there are also people whose experience is just the opposite. I guess, if all dongles come from Amazon and come from China where they are bought for $1 a piece and sold here for $18 a piece, not all of them are created equal.

You have no way of telling if it is going to solve the problem or not going to solve the problem unless you try.

Zwift does use cloud based computing for the game. The servers which Zwift runs on belong to Amazon Web Services. And mind you, Zwift uses several servers in parallel.

If you were a Zwift software developer, how would you design the algorithm so that you can continue riding after the program loses connection to your trainer and stops getting data about your power and speed? Like, would it feel weird if you get off the bike to see that in Zwift you continue climbing the mountain, or that your speed would not change no matter how hard or how easy you pedal?

From what I read on forums, when Zwift freezes or crashes, it is more often than not an issue with drivers or hardware on the computing device. Granted, it is hard to troubleshoot on a mobile device.

If Zwift loses connections to cloud servers, but is still connected to your trainer, you would continue riding (perhaps alone). You can test it for yourself - just discontinue internet after login. You can ride for hours without internet.

It is very easy to blame everything that does not just work on Zwift, but in most cases, it is our issue. You see, Zwift did not built your trainer, did not buy your tablet for you, did not provide you with a BT dongle, did not set up your system. They own the software, we own everything else. They may help us to troubleshoot, we help each other to troubleshoot, but ultimately, we own most of these issues. Once the cause of the issue is figured out, in retrospective, it always seems to be so easy and obvious. The path to success is not to make any assumptions and not think “my setup is perfect, if it does not work, it is Zwift’s fault”.

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This thread suggests that other people, for some reason, also report connection issues with Galaxy S7.

That thread is about the Galaxy S7 phone, which is a couple years old. One of my devices is a Galaxy S7 tablet, which as of today is the latest model in the Samsung tablet line.

Then I got it wrong… S7 phone is at least 4 years old. I had one of those.

Sorry…