I would like to know how much is the compression speed of a front fork (travel 120 - 160 mm) during a strong braking. Suppose the total weight of the bicycle + rider 95 Kg. Moreover I would like to know the time that pass between the action in the brake leverage and the starting of compression of the fork (dive). Is 0,03-0,05 sec a good estimation?
This depends on:
Rider's centre of mass relative to the front axle (x and y). Fork spring rate or air pressure. Fork damping settings. Braking force over time. Fork offset and frame head angle.
Could be calculated with something like Matlab but you're looking at university-level vehicle dynamics modeling.
Far easier just to test it.