Wattage drop from iphone to apple tv

I have been using the Zwift app on my Apple iPhone 6+. Recently, I’ve purchased the latest model of the Apple TV 4+ and installed Zwift. When I’m connected to my ATV4+, my wattage and speed drops and is drastically different than my iPhone. For example, on my iPhone, I can leasurely ride around 125 watts and the speed matches my output. On my ATV4+, my wattage drops to 40w and a very slow speed. Cadence matches and other settings are equal. I’ve even turned off my bluetooth on my phone to avoid conflicts.

I have a standard trainer (not smart) and connect to my bike’s cadence and speed sensors.

Does anyone have a similar issue? This is very frustrating.

Thank you.


This sounds like a setting issue. Maybe you overlooked something :man_shrugging:

You selected the same trainer on both platforms? Tire size setting is same on both platforms? Same speed sensor detected on both platforms? Can you provide screenshots of the pairing screen from both iPhone and Apple TV for comparison?

Thanks @Lin_Alan. I’ll look to get more screen shots but yes, my settings are the same. This is from my iPhone 6+. On Apple TV, the cadence is the same but the wattage would be around 45 to 50 watts and my speed barely above 3 to 5 mpg.

I should have mentioned that I’m using a Bontrager Cadence/Speed sensor with my Zwift. I had my bike computer running to confirm my cadence was exactly the same. I’ll look to provide a comparison sometime tomorrow. Thank you for replying.


Make sure that the bike computer is paired via ANT+. To be sure, remove the Bluetooth pairing in the bike computer settings if you have previously paired it via Bluetooth. Why? Well, the Apple TV can only do Bluetooth. Also, the Bluetooth connections are 1-to-1 meaning that if paired to your bike computer, the sensor won’t pair to your Apple TV or vice-versa. That said, I’m not sure where the numbers would be coming from if not your speed/cadence sensor. But, check it out anyways.

My bike computer is a Bontrager 300 and it pairs with a Bontrager 300 cadence/speed sensor via ANT (not Bluetooth and can’t change on bike computer). Pics provided.

My phone and ATV can connect to the cadence/speed sensor via Bluetooth. (I’ll get those screen shots later today). I did go as far as to turn off my Bluetooth on my phone and connect to the sensor from the ATV exclusively.

In addition, both my ATV and iPhone are connected to my home network. My Zwift Companion app can see the results shown from the ATV without Bluetooth enabled.

I’ll get you screen shots from both the IPhone and ATV, but I wanted to clearly explain my setup.

Hope this helps.image

@Lin_Alan, I have found my problem.

Tried again but this time I looked at everything with fresh eyes. My ATV matched my cadence and speed. At the main screen.

On this next screen, look at device status, the speed sensor in the upper left showed blank.

Went back to my configured Bluetooth screen, for the speed sensor, it always start with my trainer unlisted… I simply had to scroll to and select my trainer, and everything matched.

Must admit, a silly oversight but that part usually is not talked about in any YouTube videos I’ve seen. Hope this post helps someone else.

I certainly appreciate your willingness to help. Thank you.


1 Like