ERG Issues with Saris M2

Hello all! I am a Zwift (and indoor training) newbie, and I’ve been having some problems in ERG mode using my new Saris M2. While doing workouts my trainer doesn’t seem to be very responsive to the power adjustments in the workout, particularly on the low power/recovery side. For instance, this morning I was doing a training where I was trying to keep a cadence of around 85-90 rpm. This worked pretty well when I was in the 170-200w zones, but when the power would ramp way up (320w sprints) I would have to get my cadence up to around 120-130 to reach that power, and when I would go into recovery (~95w) I could only reduce power by slowing my cadence WAY down and would hit the “spiral of death”, and I had to keep my power up at about 165w (at the lower cadence, ~55-65 rpm) to even keep the pedals turning. After struggling with this for around 3 sprints I finally started turning ERG mode off during recovery to get my power level down, then turning back on for the sprints. Tire pressure is good, clutch knob is good, and I’ve been performing cold calibrations using the Saris app before I ride each morning. (Maybe I should be warming up before calibrating?)

I really love free riding and routes in Zwift, and I REALLY want to use the structured workout features, but with how ERG is performing currently workouts are starting to feel unusable in ERG mode. I know I’m probably just making some kind of newbie mistake and/or missing something… any suggestions?

Many thanks in advance… I’m really excited to be a part of this community!

Relevant Info:

  • Usual Gearing: Big ring, middle cassette
  • FPT 187, 97kg
  • Zwift App (z1.0.57840) macOS Catalina
  • Saris M2 Trainer, Firmware Updated (v31.063)
  • iOS Saris Utility v1.1.15
  • Bluetooth connection to my iMac

Does it make any difference if you go on the small ring and middle of the cassette? Sometimes people find that the small ring works better for ERG mode.

Not really, though I’ll give it another try tomorrow morning. This seems to happen regardless of my gearing (I’ve tried a pretty wide variety). One thing I haven’t tried is calibrating using the Zwift spindown calibration, which I’ll also try tomorrow.