So with tech topic about instant center and anti-squat we have the reverse to consider. The same geometry that affects acceleration, also goes into deceleration (braking).
The exact opposite reaction will happen during braking. If your instant center is on the anti-squat line the car should remain relatively flat during braking. If you move forward or aft of that line, then body movement will start to happen which may or may not be ideal. As with everything in the suspension world a balance is needed. The suspension that has the right balance for the conditions will always be more comfortable, safer, and quicker than one that isn’t balanced.
So now that we have talked about acceration and deceleration a bit time to discuss what happens when we make a turn. During a turn all of us have felt the body roll. Now think about at what point does the body roll about? That is called the roll center. Typically on the front A Arm suspension this roll center is ~4″ below the ground level. On a rear suspension it is around 8″ above the ground level. This creates an axis between the 2 points that the body rolls about.
When discussing roll center, the center of gravity for the vehicle comes into play. The closer we get the roll center and center of gravity to match each other the less leverage the weight of the vehicle has to create body roll. The further away CofG is from the roll center the more body roll we get.
Your first thought would be to make them equal, but that is now always the answer. We want/need some body roll to transfer weight to the outside tire for traction purposes. How much goes back to balancing everything again. Ideally you would transfer just enough based on track/road condition and no more. Being able to adjust the roll center can be a great tuning tool.
So those that thought controlling body roll with larger and larger sway bars isn’t always the answer.
Without getting too deep, consider this. By adjusting the rear roll center aka rear tire traction, we can also adjust how much a car understeers or oversteers? Let that sink in, as in the future we will discuss those terms and be able to create that balance that is key.