Bluetooth improvements for controllable trainers & treadmills [January 2022]

We’re making some changes to the way Zwift works with controllable trainers and treadmills over Bluetooth. Over the past few days, the server logs show the majority of supported smart trainers are benefiting from improvements to the way they apply resistance as gradients change on hills.

We are aware of bugs impacting some unsupported controllable trainers, including:

  • Shift Smart Trainer
  • STAC Zero Halcyon Smart Trainer
  • Renpho AI Smart Bike
  • InsideRide SmartPower Resistance Control

Now that we’re aware of these issues, we’re reviewing our code changes and are looking at how we improve the experience for those trainers as well. We’re planning on a fix as soon as possible.

Are you able to expand on what these improvements actually are? I have always used ANT+ without any issues at all, but I’m not averse to the idea of swapping to Bluetooth if the experience is notably improved in some way. Thanks.

1 Like

Right on! :muscle:t3:

i’ll second @Dave_ZPCMR question – more details please!

here’s some questions i’d love answers to:

  • is this for all OS’s? or just iOS?
  • are you addressing the FTMS feature of bluetooth?
  • are you ONLY addressing “controllable”, or the bluetooth connection to the trainer more generally?
  • should i try to upgrade my firmware on my trainer? or is it safer to stay on the older version?
  • is this direct-connect bluetooth only? or does it apply to companion app-as-bridge, too?
  • your post title says “controllable trainers and treadmills”… but will this affect HRMs or cadence sensors connecting via bluetooth, too?
  • are you writing linux drivers for bluetooth so we don’t have to use the companion app to connect? (sorry i couldn’t resist that one)

I have a taxc Bushido which up until today connected via blue tooth with no problems. Today the controllability element wouldn’t sinc using my iPad but was fine when I used my laptop and ant. Has anyone else had any issues?

Hi there since a couple of days my trainer (Senz S5000 with iConsole computer+0080, this is a ANT+ BT computer) is still recognized with Zwift but after starting the ride no data is collected in Zwift. No speed and cadence is measured, my avatar is not moving. I tried another iPad, but the same issue. Re installation doesn’t help.


Twice today my wahoo tickr has frozen on starting the ride & once yesterday…

Works fine with my garmin watch, hadn’t seen this issue for a few months…

To fix, have to take battery out and reseat it.

It’s not battery etc before you point this back to the end user…


I have a Nero Exercise bike with Bluetooth. It was working before the upgrade but has stopped since - same symptoms as you. Have you had any luck reporting this to support? The chat option doesn’t seem to work!

I came here looking for information about the last software update which appeared to break my Stac Zero Halcyon trainer resistance in both free ride and erg mode. I’m surprised to see it is considered “unsupported”. I hope it can be fixed shortly as I’m otherwise very happy with this trainer.

Also using the Stac zero halcyon and noticed no more sim mode…hopefully they fix this soon, or else I guess looking into ANT+ adapter if that’ll make it a “smart” trainer again.

Major issues with Bluetooth, ATV and a wattbike atom this morning in the household. (Not me, I woke up to a seriously pissed off partner)

Getting an error saying need to wake devices. Connected fine to IOS/IPad after person had spent an age trying to resolve ATV issues so not end device issue.

To follow up on the above…

ATV no longer finds device
IOS finds it instant

Tested with 30 seconds of each other, Atom was not connected to iPad when failing to connect to ATV



RGT working fine on sane ATV

@shooj is this a known issue, how is this overcome?

I have emailed support today, so hopefully an answer soon.


Dave, are you using an USB cable 5+ meters in length to your dongle?
If so, considder trying an active usb-cable.
I’ve been having issues for two years with a 5m usb-cable, bought a 7m long active cable (cable with a built in amplifier) and now all my devices work perfect all the time.
ANT+ is decent for a good connection, but if you CAN use bluetooth, you should as it is much more responsive.

did a ride today, and had to quit out because there was a noticeable “delay” between putting in effort on my bike and having it register in zwift.

kickr v5, bluetooth connection to windows.

quitting out of zwift, re-opening zwift, then re-pairing the trainer fixed it, but it was very strange.

ANT+ is perfectly responsive for me already. Having used an extension cable for years, I recently got rid of it and plugged the dongle directly into the PC. I still typically get less than 4% rxfail rate and never have any dropouts so it turns out the extension wasn’t necessary in my setup. I’ve no reason whatsoever to ditch ANT+, was just wondering what the ‘improvements’ on Bluetooth are meant to be.


Since the update the resistance control on hills seems totally out of sync. (Latest 4k Apple TV/Kickr 18)

I am on a Neo, original model – and in my three years on Zwift never had an issue with bluetooth and logging on, always perfect. BUT in the past month or so since your last big update, pairing is hit and miss – tonight it wouldn’t pair at all and this has been happening increasingly frequently. I turn off the turbo, bluetooth, the laptop, etc. etc. nothing works.

and when I do get on, there can be funky stuff with how it reads the gradients. the delay is also getting worse.

Really need help, as it is a real problem that I can’t log on at all.


I should add it seems to get worse with each patch - that I can’t even pair at all is crazy. and my bluetooth is working, as it pairs with other devices like my phone.