Ramp Test FTP vs Garmin Edge FTP

I did a ramp test today which resulted in a new FTP of 285. I then did Collins. After the ride (my Garmin Edge 830 recorded this as one ride) the Edge announced it found a new FTP of 315. Does anyone know how the Edge calculates FTP? How does your, ramp test derived, FTP compare with the one calculated from Edge head units? Both TR and the Edge were paired to the same (Vector 3) power meter

Don’t know the how but ignore Garmin. Work with TR’s recommendation.


Just a guess, but the garmin may correlate HR with the effort. If the HR max is entered incorrect, then it could assume you weren’t going as hard as you could be.

It’s anyone’s guess.

Here’s mine:

int ftp = random.Next(200, 400);

Last I knew, Garmin is using FirstBeat both for FTP and VO2max estimation. Their general technology is to look at trends in heart rate vs. power. Their writeup suggests that the FTP estimation is based on HRV within a workout.

There are lot of ways of estimating FTP. Golden Cheetah fits a model to your power curve, which requires that you do some short and long max efforts (but not in the context of a test). I think TrainingPeaks / WKO does the same. Intervals.icu uses a single short max effort. All of the models and tests are susceptible to different kinds of bias.

Since TrainerRoad workouts and plans are designed with the FTP results from their tests in mind, unless you have a good reason to believe the test isn’t working for you, you should use the TrainerRoad test results.

Edge 530 online manual:

Since the last Edge 530 FTP update in October (reasonably accurate), I’ve only been doing group rides outside and haven’t received a single FTP update. And I record all of my indoor training on 530. Go figure. I think the FirstBeat algorithm needs speed and power.

The vo2max estimates work on indoor training rides, and I’ve found them to be comparable and consistent to other estimates.

I believe it calculates best 20min power and multiply by .95 Did it get power from the same source?

seems about right haha

I use TR inside and Garmin outside, same PM. I get roughly the same numbers, within a couple watts. - Sina