Nobody is building ebikes that are physically speed limited by the motor windings. The top speed of a motor depends on load, and it's impossible to predict the

Nobody is building ebikes that are physically speed limited by the motor windings. The top speed of a motor depends on load, and it's impossible to predict the exact load of a motor in a bike with a rider. Even if you could, the amount of excess torque available as you got near the top speed would be tiny - it wouldn't be fun to ride. Speed limits are universally based on measured speed - either at the wheel or motor.