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?

  • No difference at all from hitting a bump, other than the bike is going down rather than the road up. Mar 28, 2016 at 11:35
  • 2
    I think you need to do some experiments. Get a gopro on 60 FPS mode, or 120 FPS if supported, mount it to a second mule bike and record your front from the side while passing over obstacles at various speeds. Bonus marks for mounting a ruler in-shot.
    – Criggie
    Mar 29, 2016 at 0:39

1 Answer 1


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.

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