Problem set 2 -week 3 challenge : Anti-Characteristics

1

• Front End Deflection Under Load:

Front end deflection = (Front Axle Weight *0.5) / Front Wheel Rate

Front end deflection = 3.34 in

• Rear End Deflection Under Load

Rear end deflection = (Rear Axle Weight *0.5) / Rear Wheel Rate

Rear end deflection = 2.99 in

• Pitch Angle:

Pitch Angle = tan ^-1 ((Front End Deflection + Rear End Deflection)

/ Wheelbase) *(180/π)

Pitch Angle = 3.69 deg

• Pitch Gradient:

Pitch Gradient = Pitch Angle / Throttle Acceleration per g

Pitch Gradient = 7.32 deg/g

2

• Front Anti-Lift Angle:

Front Anti-Lift Angle = tan ^-1 ((FICV - Tire Radius )/ FICH )*(180/π)

Front Anti-Lift Angle = 3.45 deg

• Rear Anti-Squat Angle:

Rear Anti-Squat Angle = tan ^-1 ((RICV - Tire Radius )/ RICH )*(180/π)

Rear Anti-Squat Angle = 6.04 deg

• Front swing arm angle for 100% anti-lift:

Swing arm angle = tan ^-1 (CG Height/ Wheelbase )*(180/π)

Front swing arm angle for 100% anti-lift = 9.84 deg

• Rear swing arm angle for 100% anti-Squat:

Rear swing arm angle for 100% anti-Squat = 9.84 deg

• Front anti-lift %:

Front anti-lift % = (Front anti-lift angle * Drive ratio)/ FV Swing Arm Angle

Front Anti-Lift % = 0%

• Rear Anti-Squat %:

Rear Anti-Squat % = (Rear anti-Squat angle * ((100 - Drive ratio)/100))/ RV Swing Arm Angle

Rear Anti-Squat % = 61.42 %

3

• Front Anti-Lift % & Rear Anti-Squat % for Zero Pitch Angle:

We know,

(e-r)/d = (h/l)+((h/l)*(W_RR/W_RF)

Where,

e = Height of IC

d = Distance of IC

r = Tyre Radius

h = CG Height

l = Wheel Base

W_RR = Wheel Rate at Rear

W_RF = Wheel Rate at Front

Equating e=16 in as given in question for Zero Pitch Angle,

e = RICV = 16 in

d = RICH = 11.30 in

Front Anti-Lift % = 0%

By equating RICH & RICV in Anti-Squat Angle, and then we imply that in Anti-Squat % formula,

Rear Anti-Squat % = 220.71 %

• Front End Deflection under load:

Front End Deflection (with Compensation) = (Front End Deflection *(100-Anti-Lift))/100

Front End Deflection = 3.34 in

• Rear end Deflection Under Load:

Rear End Deflection (with Compensation) = (Rear End Deflection *(100-Anti-Squat))/100

Rear End Deflection = -3.61 in

• Pitch Angle:

Pitch Angle = tan ^-1 ((Front End Deflection + Rear End Deflection)

/ Wheelbase) *(180/π)

For the calculated value of RICH = 11.30,

Pitch Angle = 0.65 deg

Assuming, RICH = 11.835

Pitch Angle = -0.0002 deg (Nearly Zero)

Google Drive Link for Excel Sheet:

https://docs.google.com/spreadsheets/d/1H2smfcJKFZiimN0GW4QUMtg69TyoL0Pj/edit?usp=sharing&ouid=102891323117469303946&rtpof=true&sd=true