With a higher static distribution of weight (high cross weight percentage of 56-62 percent
There are several critical reasons why a balanced setup is essential to optimum chassis performance. First of all, once balanced, we can accurately predict load transfer. This is the primary reason why the "roll couple distribution" technology failed. An unbalanced car redistributes the load on the four tires in a very unpredictable way. If we cannot determine the desires of each end of the car, balanced or not, we cannot accurately predict the exact amount of load transfer and the resulting loads on each tire.
Secondly, we will have less (almost non-existent) chassis flex with a balanced setup. Compliance, or flexing of the chassis, cannot occur if we remove the forces that cause this to happen. In 1995, I was asked by a prominent race engineer working with a top Cup team what I thought of compliance. I asked if he meant chassis flex, and he replied yes. I told him that if we could remove the forces that ultimately try to twist the chassis, we could mostly eliminate chassis flex. That simple answer astounded him, because no one had approached the problem from that angle.
Last and most importantly, we need to have two sets of tires that are each doing equal amounts of work. Which two are paired depends on the static load distribution. In stock car racing, we will almost never have all four tires doing equal work (having equal load on each tire) under most current left side weight rules. If we can set up the car so that after the load transfers in the corners, we have equal working pairs of tires, then we will have a true balanced setup.
At the recent Charlotte 600 race, Kasey Kahne ran up front all day and eventually won. It
If you carefully watch an F1 or Sprint Cup car going through a turn, you can see the degree of balance that exists. A car that is twitchy or rocks as it turns is not very balanced. The handling may be neutral for the time being, but that does not mean both ends of the car are in sync. A car that loses a lot of speed on a particular run on the same set of tires is not very well balanced. The primary cause of the loss of speed due to an unbalanced setup is because the car's handling balance changes to tight or loose.
Unbalanced setups abuse one or more tires. It is this abuse that causes the tires to wear or heat up excessively. Balanced setups distribute the loads evenly on each pair of tires. This provides maximum traction as well as a consistent handling package.
The advancements that have come from this new approach to chassis setup benefit all of racing. The fact that it came from within the ranks of stock car racing is not hard to understand if you have been around these types of racers for long. They are the most innovative and industrious group that exist in our entire world. The racer digs hard, is not afraid to get his hands dirty to affect change, and when some new technology comes along that proves itself they, as a group, jump on it regardless of what the higher learning institutions continue to teach.
In the next installments we will learn about the specific dynamics of each suspension system and how we can measure and adjust each to find that perfectly balanced setup. These methods have been used in most forms of motor racing around the world.