Calculate approximately G-force applied on Car shock absorber

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ELEFANTOMET
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I have to do some dataacquisition from a car with some accelerometers.

4 accelerometers is placed on the wheels before the shock absorber. And i need to calculate the maximum applied G-force on the accelerometers.

Just an approximately value, not taking in account the type of wheel, airpressure in wheel etc.

Scenario 1:
Steady speed of the car driving on normal tarmac is 110km/h.
Weight of car is 2000kg
The car is driving over a small bump with a height of 5cm

Scenario 2:
Steady speed is 50km/h
Weight 2000kg
The car is driving over a regular speedbump, approximately height of 30cm

Seeing the bump on the wheel as if was a regular spring, i would calculate acceleration from
A=5cm
ω=sqrt(k/m) (not knowing the spring constant, i just took some samples from 0-500Hz as a value, what's realistic here?)
a=-ω^2*A*cos(ω*t)
with a.max being -ω^2*A

and then divide final max acceleration with 9.8m/s^2. But this seem to give me abnorm large value of g-force.

Any help, to how to calculate this the right way?
 
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The rise/run ratio of your bumps will have some determination of your G force.
A slightly sloped bump gives less G force than a sharp bump, due to Ft.

A 30 cm bump - this is a regular sped bump height?