Quote:
Originally Posted by u/Josh
I'm still getting 21.11 N/mm. Perhaps your are still in units of Kg/mm?
The good news is this works out to be 1.6 hz ride frequency. Anyone know why we see the highest gain in the bode plot at around 5 hz not 1.6 hz?
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Mistake was exactly what you said. Used an online calculator, and I shouldn't have trusted it.
The original post is updated.
spring rate = 4 * pi^2 * ride frequency^2 * sprung mass * motion ratio^2
22970 = 4 * pi^2 * f_r^2 * 280.4 * (1/0.92)^2
f_r = 1.325 Hz (front)
Notice that the motion ratio is inverted. If you leave it as 0.92, you will get 1.5 Hz as you got.
The rear comes out to be 3.8154 Hz. It is definitely stiffer in the rear, but it doesn't quite feel THAT stiff. Once we can confirm the rear motion ratios, we can state it with confidence.