ORIGINAL: Jailbird1818
#1 is common with sensorless BL systems. It's called cogging. That is the rotor passing through each magnetic field in the motor.
#2 is tire balance, stick on weights will cure this. Nothing sounds ''wrong'' with the truck. Balancing the tires is something you want to do.
-JB
Cogging is not the norm with brushless sensorless motors.. Its a side effect of underpowered batteries.The batteries cannot supply the amps or voltage required by the motor.. ..Lipo's will cure the issue and so will reprogramming the esc to run on Nimh batteries.. I've had that issue with my Mamba until I reprogrammed the esc to know it was running Nimh batteries and it worked much better.. still a little cogging if I really feathered the trigger.. I only run lipo's now and there is no more cogging.. You will still feel the motor stutter a bit, thats how the sensorless work, but nothing that I would call cogging...
Tire weights are a must with the high speeds of the brushless system.. You won't realize them till you add more voltage, but it will be much more obvious when you do.. stick on weights are the way to go..