I have a large gates pulley that i am using for the transmission of my servo driven bt30. It is an 80t 5mgt mounted on the shaft of my 1kw servo. It works but this pulley has a huge amount of inertia to it and greatly limits how fast i can accelerate my spindle without faulting the servo, almost an inch thick and 5 inch diameter solid steel. Since i am only pushing a few hp peak at the most, this pulley does not need to be that beefy and i could about cut the inertia of my whole system in half by hogging out the center of this pulley and replacing it with a spoked aluminum hub. Question is, how much material can i remove before the pulley starts distorting and going out of round? Im not sure what exactly the process is for making these pulleys or what the material is. I would think the rough shape is probably cast and then post machined so probably somewhat stable as i remove material but i just dont know. Do i need to worry much about distortion as i machine it?