Maximum "DEFAULT_AXIS_STEPS_PER_UNIT" ?

Hi, I have been given a nema17 stepper with a 64:1 gearbox attached.
I have modified and made a 'replicator 2 simple extruder' to fit on the end and all looks good. (pics attached)

My original configuration.h looks like this.
#define DEFAULT_AXIS_STEPS_PER_UNIT {98.52216748768474, 98.52216748768474, 98.52216748768474, 134.76645233}
#define DEFAULT_MAX_FEEDRATE {600, 600, 600, 100} // (mm/sec)
#define DEFAULT_MAX_ACCELERATION {1200, 1200, 1200, 300} // X, Y, Z, E maximum start speed for accelerated moves.

I assume I need to increase the 134.76645233 value by a factor of 64?
However, when I try to do this values over 3000 result in just vibration.

Have I maxed-out the stepper controllers?
At 3000 steps I am only getting about 17mm for 50mm demand.
Is this ratio too high.

TIA

Bixx

Decrease your max feedrate. The problem is that you are now toggling the steps too fast and the stepper doesnt have time to make the next step before the previous is reactivated. Slow the max feedrate to around 14 or less. Tweak this setting until you find an appropriate value.

@CidVilas,
I have done as you suggested.
I had to reduce the max feedrate to less than 2 in order to go to 8700+ and final tweaking gives 8776.0125663 and 2.1 for 50mm demand for 50mm output.
Now to try it and see if I have any issues with retraction as the feedrate is a long way from the 40mm/sec of my current settings.

Thanks for the advice