The distance between the roll center and the center of gravity is called the roll couple. The roll couple is the lever arm that centrifugal force working on the CG uses to make a car lean over in a turn around the roll center. In a rear- or mid-engine car, these approximations apply to the opposite end of the car.

The longer the roll couple, the more weight is transferred to the outside wheels during cornering and the more the car will want to roll in a turn. A longer roll couple makes cars slower to respond to steering input. The resulting weight transfer from a long roll couple also uses the inside tires less effectively during cornering, thereby reducing the available grip.

The often-overlooked disadvantage to lowering is that roll center drops more radically than the center of gravity on most cars. This increases the roll couple and can cancel any weight transfer advantage. The huge roll couple created by overlowering will require an overly stiff suspension to control body movement.

And when your suspension is too stiff, it won't absorb road irregularities effectively, which will make it harder to keep the tires in contact with the ground. You can't drive fast if your tires aren't on the ground.

On most cars, the ideal location for the roll center is 2 to 5 inches above the ground for the front suspension and 4 to 10 inches above ground for the rear suspension. With the rear roll center higher than the front, the car will transfer more weight to the front, making it more likely to understeer. Most purpose-built racecars utilize this design because it allows them to be tuned for slight understeer at high speed and more oversteer at lower speeds.