While their controller seem a poor design, something they also put 3-4 magnets (little strong bugger) to hold the disk I’m guessing to reduce friction.....

I have since removed all those magnets by taking the wheel apart and punching them out, on the 3 set of JP brake I have....and that help in getting some brakes at low to mid point, I’m on a slider so my result may be different.....I also change 2 of them to the Xicoy controller with the Gyro...