The way we recommend calculating/measuring the Motion Ratio is by the following steps:-
- Set the chassis level on axle stands with the wheels at full droop and off the ground.
- Remove the springs from the shock absorbers and refit the shocks to the vehicle.
- Take a datum measurement of the vertical distance from the centre of the wheel to the ground measurement x ( ___mm).
- Take a datum measurement from the centre of the lower shock mounting bolt to the centre of upper shock mounting bolt measurement a ( ___mm) (shock open length)..
- Jack the wheel up till the shock just touches the bumpstop, taking care to ensure not to lift the chassis off the axle stands.
- Re-measure the distance from the centre of the lower shock mounting bolt to the centre of the top shock mounting bolt measurement b ( ___mm) (closed length)..
- Re-measure the vertical distance from the centre of the wheel to the ground measurement y ( ___mm).
- Subtract (x) from (y), this is vertical wheel travel w ( ___mm).
- Subtract (b) from (a), this is shock travel s ( ___mm).
- The motion ratio is (w) divided by (s) ( ___:1)
NB Please ensure all measurements are to the nearest millimetre as the numbers recorded are squared as part of the spring and damper calculations.