Racerxx,
I have one of the motors right here and turning it with no load produces cogging and not due to the belts. Turn the one you have there, there is cogging inherent in most all DC motors as the poles come into alignment.
There should be very little feel to the belts when turning and you should not feel the teeth engaging. You took the motor out and turned the rim? So only one belt was connected then? If you can something is either adjusted incorrectly or the wrong pulley/belt combination is being used. There should be a smooth transition of the teeth meshing. When gears are aligned incorrectly, generally too tightly, you can feel this. When they are properly meshed, you feel nothing.
A simple way to experience the cogging is to connect your wheel to something and turn the rotation down to 90 degrees. Turn it past the fake bump stop, then turn slowly. You will feel each cog and hear the motor, it's not the belts
You will barely feel cogging without powering the wheel. It's only when power is applied and you are moving the wheel against force feedback that it becomes apparent.
As for the CSR Elite and CSW, I'd have to dig out the photos I took, but from the one I have handy, it does not look to have teeth. This is why I stated that you may not be able to keep them aligned. When the motors fail in these, it's always one of them. One is bound to be the weaker of the two and will at some point fail.
If the motors are attempting to reach their respective poles and cannot, even at rest, they will constantly be at odds with each other. They are not only fighting against the user, but one another. As well, because the sensor is no longer on the motor but the main hub, the wheel electronics do not realize this is even happening.