The Centre of Gravity (CG) plays a crucial role in vehicle dynamics as it impacts stability, handling and performance.
Ways in which CG influences aspects of vehicle dynamics:
Stability and Rollover Risk
Handling and Cornering
Braking and acceleration Dynamics
Ride Comfort
Aerodynamics
Weight Distribution and Traction
Suspension Design
Now lets see exactly how it influences all of these
1. Stability and Rollover Risk
Higher CG: A vehicle with high CG like SUVs (Sport Utility Vehicle) or Trucks are more prone to tipping over during sharp turns or when traversing uneven terrain. This is because the rollover threshold is lower the higher the CG.
Lower CG: On the contrary sport cars and sedans with low CGs are much more stable and less likely to roll over, which allows for safer high-speed cornering.
2. Handling and Cornering
A lower CG improves cornering performance by reducing body roll. It keeps more of the tire contact patch, on the ground maximizing the grip.
Vehicles with higher CG tend to experience more body lean during cornering which can Lead to understeer or oversteer, depending on weight distribution.
3. Braking and Acceleration Dynamics
During braking, a forward shift happens due to inertia, a high CG amplifies this effect, increasing the load on the front wheels while reducing rear-wheel grip, which leads to instability.
In acceleration, the rear wheels experience a higher load transfer with a high CG, potentially reducing grip on the front wheels, which severely impacts steering control.
4. Ride Comfort
Vehicles with a lower CG generally offer smoother rides as they are less affected by lateral and vertical forces caused by road irregularities.
Higher CG vehicles may feel more “bouncy” or top-heavy especially on uneven surfaces.
5. Aerodynamics
Lowering the CG often involves lowering the entire vehicle, which can reduce aerodynamic frag and improve high-speed stability
A higher CG vehicle typically will have more frontal area, leading to more drag.
6. Weght Distribution and Traction
CG location (forward , rearward, or centered) affects traction:
Front-biased CG: more grip on the front wheels, leading to understeer.
Rear-biased CG: more grip on the rear wheels, causing oversteer.
Balanced CG: optimal for even traction and neutral handling.
Vehicles like mid-engine sport cars aim for a balanced CG to Maximize performance.
7. Effect on Suspension Design
Suspension systems need to be tuned considering the CG to control the weight transfer and to maintain tire contact with the road.
A high CG demands stiffer anti-roll bars and dampers to counteract body roll.