Calculate suspension motion ratio (installation ratio) from spring and wheel displacement or geometry measurements.
Input Parameters
Results
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Motion Ratio
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Wheel Rate
lbs/in
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Ride Frequency
Hz
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Static Deflection
in
Note: Motion ratio is typically 0.5-1.0 for most suspensions. Double wishbone: 0.6-0.9, MacPherson strut: 0.85-1.0. Lower MR means softer effective wheel rate.
Reference
Motion Ratio = Spring Displacement / Wheel Displacement
Wheel Rate = Spring Rate x MR²
Static Deflection = Corner Weight / Wheel Rate
Ride Freq = sqrt(Wheel Rate / mass) / (2 x pi)
MR < 1.0 (spring moves less than wheel)