Help! My Vortex Smart isn’t changing resistance on hills!

This is a common issue new Vortex Smart owners encounter–I know I did! I thought I had done everything correctly–I unpacked my Vortex, plugged it in, updated the firmware, calibrated it, then fired up Zwift and paired it up. But when I started riding the hill of Watopia I found myself thinking, “Is the resistance not changing, or am I just in really good shape?”

The solutions to this issue are usually simple:

Solution 1: Update Firmware

If you don’t have at least firmware version 3.1.7 installed on the trainer Zwift will be unable to change resistance on hills.

Solution 2: Disconnect Bluetooth

Zwift cannot control your Vortex’s resistance via ANT+ if you are connected to it via Bluetooth. Strange but true. So while you need to connect to the Vortex via Bluetooth to calibrate it, you’ll need to disconnect it from your phone’s Bluetooth in order for it to respond to inclines properly in Zwift.

UPDATE: thanks to the June 2nd Zwift update you may also control your Vortex entirely using Bluetooth via the Zwift Companion app.

Solution 3: Pair as Controllable Trainer

Make sure you pair your trainer as a “Controllable Trainer” (bottom-right of pairing screen) AND as a power meter (top-left of pairing screen). You need to do both for it to function properly.

What to do before calibrating your Tacx Vortex Smart

There are two things you should do before calibrating in order to ensure accurate power readings.

First: Inflate Your Tire

Tacx recommends 7-8 bar (~100-120psi). To keep things simple I try to keep my tires at 110psi, which is what I ride at in the real world.

Why does it matter?

Your Vortex will calibrate accurately at any reasonable tire pressure, but unless you want to calibrate before every single ride you’ll want to decide on a consistent tire pressure to maintain. Otherwise, if you calibrate at one pressure, then hop on and ride at another pressure days later, your power readings will be off.

Second: Warm Up Your Tire

Ride for at least 3 minutes at a decent power level so the rubber is warm. If your tire is especially cold you’ll want to go longer. I recommend a 10-minute warmup.

Why does it matter?

As your tire warms up it becomes more pliable, effectively reducing the tension of the tire against the roller. In terms of power numbers, what this means is if you calibrate with a cold tire, the Vortex’s power numbers will be significantly higher than normal once the tire warms up.

(I experienced this myself accidentally in a race once: my numbers were ~60 watts higher than they should have been, because I calibrated on a cold tire! For a while I thought I was just having a really good day, but when Zwift wanted to update my FTP to 60 watts higher than it had previously been I knew something was afoot.)

Updating your Tacx Vortex Smart firmware

Your Vortex is a computer, and sometimes the code which runs that computer needs to be updated. Keeping your Vortex’s firmware updated helps to ensure your trainer is functioning optimally.

Note: you don’t need to check for firmware updates on a regular basis–the free Tacx Utility app does this for you when you run it, so whenever you calibrate your Vortex it will also check for updates.

Required Update

While firmware updates are somewhat “optional,” your Vortex won’t work with Zwift until you install at least firmware version 3.1.7, which is the update that allows Zwift to talk back to the Vortex to adjust tension to simulate inclines.

Note: most Vortexes being sold now already have this firmware version installed, since it was released July 2015.

Updating Your Firmware

Updating the firmware is an easy process. The app may prompt you to update the firmware, or you can click the menu bar (3 lines) at the top-left and choose “Update”.

If an update is available the app will reboot your trainer, upload the firmware, then prompt you to unplug the power cord and plug it back in.

Once you’ve done that you should see a screen confirming that your trainer is running the latest firmware.

Calibrating your Tacx Vortex Smart

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Your Vortex must be calibrated in order to give Zwift proper power readings. Calibration is a fairly painless process using the free Tacx Utility app (available on iOS and Android).

Note: this guide below uses the iOS app. I assume the Android version is similar.

Before you begin: make sure you’ve inflated and warmed up your tire. Read why here >

Step 1: enable Bluetooth on your phone, open the app, and connect to your trainer. You will see a green checkbox at the top-right once it is connected.

Step 2: click the menu bar (3 lines) at the top-left and choose “Calibration”.

Step 3: The app will prompt you to start pedaling and speed up to 30km/hr, then stop. This “spindown test” lets the app sense how much tension is on your tire.

Step 4: if you’re anywhere between the two white lines (figure 1), you’re all set. If you are outside the white lines (figure 2) you will need to adjust the tension accordingly then calibrate again.

That’s it! Now just turn off Bluetooth (or at least disconnect from the trainer in the app) so Zwift can work properly.

There was an error during calibration

Note: if you receive a notice that “There was an error during calibration” there are two probable causes:

1. Your trainer’s tension is way too loose or way too tight. Try adjusting it and re-calibrating.
2. Your trainer’s firmware is out of date and not speaking properly to the app. Update the firmware then try again.

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