Cadence too Low

I’m using a 20 year old Blackburn Mag 3 “dumb” trainer. But I do have brand new Garmin Speed and Cadence Sensors.
Started using Zwift a couple of weeks back, and happy except for the Candence, no matter how I spin always shows a very low number.
It always says it’s paired, but drops it way low on climbs. Anyone had a similar issue?

Hi @Brendan_Cook

Welcome to the forum.

It can be that the magnet is not close enough to the sensor.

Hi, no sensor on the Speed 2 Garmin, it has a built in weight that shift on each rotation. I’ll give it a shake…