This is a question a lot of people new to indoor virtual cycling ask – why is the distance and speed on my head unit different to FulGaz? The short answer is, it doesn’t matter. Simply put, the two will never perfectly match – and that’s not a problem!
To delve a little deeper, FulGaz adjusts your on-screen speed based on power output and the gradient of the road (plus other calculations using rider weight, aerodynamic drag, rolling resistance, etc).
Your Garmin or Wahoo (other brands available) head unit is receiving basic data from either rear wheel speed for older wheel-on turbo trainers or a combination of power and the “speed” your trainer is spinning at. Because your head unit isn’t communicating directly with FulGaz, it doesn’t know your weight or aerodynamic drag or whether you are crushing a famous European climb or chasing a speeding Chris Froome in Australia!
It can be quite confusing seeing your on-screen FulGaz speed vary so much from the speed on your Garmin, but my advice is to simply turn off your head unit! It’s not necessary. Use the data from FulGaz.
FulGaz can automatically upload your ride to Strava, Training Peaks or Today’s Plan. A complete “.fit” file is also emailed to you for manual uploading to your software of choice once you complete your ride. All the data you need is included, so there is no need to “double record” your ride using a separate head unit.