Suggestion for Zwift developers: latency improvements (power)

Hello together,

I’m using Zwift with a simple Tacx vortex trainer which I set up with ANT USB dongle because Bluetooth is not reliable enough with my laptop.
Power and resistance come always too late and the latency can be something like 1/2 second.
This is a bit annoying, especially while training/racing in a group where you can get dropped even if you ride strong (typically end of a Hill) or move to the front even when you don’t want to (typically beginning of a hill).
Would it be possible to introduce a latency setting so that the power/resistance is sent to the smart trainer 1 or 2s earlier than the picture displayed? Creating a configurable delay between resistance profile and graphic would solve the issue and doesn’t look complicated to implement on a first sight.

What’s your opinion? The suggestion probably already came but I didn’t find it here.
Thanks in advance !

it’s probably specific to the unit and not something zwift can do a whole lot to influence. I just swapped from a direto X to a saris H3 and one of the first things i noticed was much lower latency

Yes you are right, it depends on the device. I don’t want to change device only because another one is faster.
And it’s exactly the purpose of my proposal: the user can set the latency parameter as needed so that every device can run synchronized with the video streaming.
And so we don’t need to change the device all the time. It’s especially interesting for people using Zwift on different locations with different devices.

If you have devices to swap between transmission types, I’d be curious to read if you find your H3 is like mine, ANT+ feels laggy and takes an age to engage supertuck compared to Bluetooth.

sure, i can try bluetooth for you later. It felt good on ANT+ yesterday though. to keep this relevant to the thread, I found that my old direto was much more responsive on bluetooth than via ANT+ so if you have the means, try pairing the unit with a different method Olga. it may not make a huge difference or any difference but it might help a little

1 Like

I have use both ANT+ and Bluetooth and did not experience lag on the H3.

Another thing with latency is it works both ways, if it engage 1sec late to a climb it will also have 1sec more resistance going over the top.

1 Like

You are right, it applies in both ways, this is what I tried to describe originally.
On mine, bluetooth is much less subject to latency than ANT+… but the connection stops much too often to ride unfortunately. For me it would be the easiest fix…

Have you tried to uncheck “allow the computer to turn off this device to save power” in the Bluetooth device settings? I was having disconnection issues using Bluetooth and after disabling this option it became stable. I also prefer using Bluetooth over ANT for the same reason as you, ANT has a delay in resistance change (specially noticeable when there are constant changes, like in Titans Grove) while Bluetooth is very smooth. My trainer is an Elite Suito.