Results of Chassis Roll
Zero Right-Front Camber Change The right-front (RF) wheel will either gain or lose negative camber, depending on the arm angles and lengths. What we really want is minimal gain in the negative direction at the RF wheel, and we never want the RF wheel to change camber in a positive direction. This way, we can maintain the same negative camber in the middle of the turn, after the car dives and rolls, that we had at normal ride height.
From extensive testing, we have determined that the RF tire likes this condition. It takes a set fairly early on entry to the corner. If the camber continues to change after that point, the tire tends to give up traction. If the camber remains the same during entry and through the middle of the turns, we can easily see incorrect camber settings by looking at the tire temperatures. Excess camber change can give false indications of the tire temperatures that we use to insure ideal camber settings.
Results of Chassis Dive
At the LF, we want to lose as little positive camber as possible so that we can start with the least amount of static positive camber. You will need to have about one-half to three-quarters of a degree of positive camber remaining in the left front wheel after the car dives and rolls. For both front wheels, the final tuning for the best static cambers is done by running the car and measuring the heat across the tires. Be sure to also look at the tire wear to help determine the best static cambers.
Excess Weight Transfer = Bad Setup The setups we run have a lot to do with our need to run excess RF camber and lower amounts of LF camber. The greater the force and weight put on a tire, the more that tire will deflect at the contact patch and the more static camber the car will need in order to maintain a solid footprint.
A setup where the two suspension systems, front and rear, are not balanced will cause excess weight transfer at the front of the car to the RF tire. In extreme cases, the RF tire will have to support the entire weight of the front of the car. Proof of this is when we see a car carry the LF tire off the track surface. At that point, the RF tire supports the entire amount of front weight.
Spindle Height Effect on Camber Change
There are varying degrees of this excess weight transfer, and we do not always see light under the LF tire. We need to maintain a more balanced setup so that the LF tire will share the load and help work to turn the car so the RF tire does less work, and therefore, will require less static camber. Low angle of camber in the left front is one of the indicators of excess weight transfer. We look at the tire temperatures and see where the inside of the LF tire is hot, then we take positive camber out of that tire. With an unbalanced setup that transfers excess weight to the RF tire, there is less force acting on the LF tire, and so less static camber is needed because that tire is doing less work.
Tracking Moment Center Throughout this whole process, don't forget to track where moment center is located from the centerline of the car (halfway between the two tire contact patches), and keep it in its proper location. The height of the roll center will change slightly as you increase or decrease the upper control arm angles. You can change arm angles and arm lengths, and still keep your correct moment center location.