Hey! I just realized there is a formula missing.
Kt = T * L * D^2
Where T is a torqueconstant for the motor reliant mostly on the magnet strength and airgap. L is the length of the stator stack and D is the diameter of the stack.
There is another Kt formula based on the actual values instead of just a constant.
Kt = 1/Kv
but depending on the Kv units it may become:
Kt = 60/(2*pi*Kv)
This turns a rpm/volts Kv into a radians/second/volts so that Kt becomes Nm/A.
An interesting thing about the first formula is it shows that, as mentioned, The relationship between Kt and Kv is inverse proportional and that length of stack has a linear relationship with Kt and Kv. What it also shows is that the diameter has a squared relationship! This is important if you need more torque. For a inwheel motor, maximizing diameter will increase torque by D^2 while increasing width only adds L.
