Motion Ratio Calculations

Setup:

Set the chassis level on axle stands with the wheels at full droop and off the ground. Place the chassis on axle stands with wheels hanging freely off the ground.

Remove springs from shock absorbers and refit shocks to the vehicle.

Measurements:

Measure the vertical distance from the centre of the wheel to the ground (x) ( mm Wheel to Ground (X) is required ).

Measure the distance between the centre of the lower shock mounting bolt and the centre of the upper shock mounting bolt (a) ( mm Shock Open Length (A) is required ) (shock absorber open length).

Testing:

Jack the wheel up until the shock just touches the bump stop, ensuring the chassis remains on the axle stands.

Measure the distance between the centre of the lower shock mounting bolt and the centre of the upper shock mounting bolt (b) ( mm Closed Length (B) is required ) (closed length).

Re-measure the vertical distance from the centre of the wheel to the ground (y) ( mm Closed Wheel to Ground (Y) is required ).

Calculations:

Subtract (x) from (y), to find vertical wheel travel (w) ( mm Vertical Wheel Travel (W) is required ).

Subtract (b) from (a) to find shock travel (s) ( mm Shock Travel (S) is required ).

Motion Ratio:

Divide vertical wheel trave (w) by shock travel (s) to get the motion ratio ( :1 Motion Ratio is required )