Torque is a variable. When the load is different and the torque is different, it will increase with the increase of the load. After reaching a certain torque, the load will increase again, and the torque will become smaller.
Is the max rpm 3500 or 4500? The selection boxes show one at 500-4500 and one at 4500 yet the description says 3500. Is it possible to get a 4500 rpm 750 watt motor?