If you’re using a wheel-on trainer that doesn’t transmit data—often called a “classic trainer”—your in-game effort will be generated by zPower, our estimated power curve. With zPower, Zwift takes data from either a speed sensor or power meter to generate virtual watts in Zwift. For the best results, consider the following before pairing your devices:
Keep in mind, zPower is a calculated estimate of your power output and doesn’t represent absolute power values. Due to a number of variables—it's likely that the data you see in-game will vary from the power you’re actually generating. While picking up a power meter will help give you a more accurate experience, a Direct Drive trainer will give you the best Zwift experience.
The Trainer: Each of our zPower calculations are based on a specific trainer. Make sure you select the right trainer in-game.
Trainer names in-game are based on physical appearance, not model name, so there’s a good chance the two won’t align. If you need help finding your trainer in Zwift, check out this article.
Tires: Make sure your tires are inflated to the right PSI and select the exact—or closest possible—tire size in-game.
Under-inflated tires may cause inaccurate readings.
Trainer Tightness: Make sure your trainer is tightened properly. If you have questions about the correct tension for your trainer, check with your hardware manufacturer.
Resistance Setting: If your trainer has a manual resistance dial or knob, set it to match the value displayed in-game when you select the device in-game. Note the Resistance Level on the pairing screen after you select it and confirm your dial/knob matches that setting.
For Mag trainers with a resistance setting cord, leave the cord flat on the ground.
If your resistance cord isn’t flat, it can throw off your trainer’s resistance.
For help with setting up your speed sensor check out this article.