I just started riding again this spring, first on a Trek Emonda Sl6 and then a Domane SL7 and I just set up my Wahoo Kickr. I started yesterday by doing about an hour on Innsbruck. Then today I figured I should try to find out my FTP, so I did the short Test (45min). I completed it best I could, but at the end it says my FTP is only 114. I am in Erg mode for the FTP.
I am 50 yrs old, but I think I’m in decent shape. I typically ride 4 days a week 15 miles per ride, and weekends 25 miles, averaging about 15.5 mph. Prior to this I worked out at the gym, mostly weights and light cardio. I’m 5’10 and 165 lbs, male.
Possibly related: I notice my Garmin will say I’m doing 20mph but on the screen Zwift says I’m only doing 8mph (just an example). Was I supposed to do some sort of calibration prior to my first ride? Or am I really not as in shape as I thought I was?
I can’t be sure that this is the cause, but I’m pretty sure you won’t get accurate results if you do the test in Erg mode. Flip to Level mode and try again.
And yes, you should calibrate the trainer using the Wahoo app.
The speed Zwift displays will rarely if ever match your Garmin head unit. Zwift uses your weight, height, weight of bike (in game), wheels, cda of your body (based on height and weight) and in game bike specs along with terrain to determine speed (along with the watts you are producing).
Garmin just knows the watts you are producing and not the slope you are on and any other drag coefficients.
You can also try the ramp ftp test as many find this easier since pacing yourself correctly for a normal ftp test is where most fail.
Calibrate using the Wahoo app and make sure your trainer is warmed up for 10 min. This should be done at a minimum whenever ver you remove your bike from the trainer.