Ride rate, Roll rate calculation : Part 1

Ride rate is defined as vertical force per unit vertical displacement of the tire ground contact with respect to chasis.

Roll rate is defined as torque resisting body roll per degree of body roll.

Assumption made in calculation.

  • 0 degree camber change with ride
  • no tire lateral distortion.
  • steady state cornering ie without longitudinal acceleration.
Vehicle on Bank

1. Aα (horizontal acceleration) = V2 / Rg

V = velocity of vehicle

R = Radius of turn

2. Ay = Lateral acceleration in car axis system = Aα cos α — sin α

As FY = -Fα cos α + W sin α (from above fig)

3. Effective weight of the car due to banking is

W’ = W.Ay

4. Effective front and rear axle weight are.

W’F = W’ (b / l)

W’R = W’ (a / l)

a and b are cg location calculation for location of centre of gravity.


Part 2