I need help with my motor tuning while. I have a fireball v90 with the probostep breakout board and drivers from probotix.com. When the motors are running at normal speed 70ipm they run fine I can try to hold on the the axis and the motors will not miss a beat, but when I am rapiding and 150ipm I just barely touch the axis the motors will bind(make the loud whining sound). I have tried tuning different settings but I think that I am beginning to chase my tail. I have checked the axis's after removing the motors and the move fine. What am I missing here will the motors always have that much less torque and rapid speeds? I have tried all of the different step modes on the motors from 16th to full, but the problem always seems to be there.

Does anyone feel that if i add a smooth stepper to the setup that it will help? If anyone has any other things that I can change in the setup please let me know.
I have read the Manuel still not 100% sure on what changing the step and direction pluse does, or if that will even help
Thanks in advance for any advice,
Tom