If using previously run tires, the age of the tire must be taken into consideration when making comparisons to other cars. If you start on stickers and run 50 laps of testing, expect to lose time because of the tires wearing. If lap times stayconsistent, the changes being made are probably increasing performance. Eventually switching to newer tires will show the positive results of those changes.
Do not chase a competitor who has newer tires. If adjustments are made to try to make up the three- or four-tenths difference in tires, you could be putting the setup out in left field, never to return. Some teams will use the unsupervised tests as a chance to "cheat" the setup and go fast. If an opposing team is too fast for your class, do not make wholesale changes in attempt to keep up. Once they return to regular competition where they must meet the rules, the times will return to normal. There's no purse for winning a practice session.
The First Set of Runs
The driver should initially make several slow five-lap circuits and then five faster circuit runs to "shake down" the car the first time out. This establishes that the brakes work as expected, the wheels are on tight, the air will stay in the tires, there are no water or oil leaks, and the transmission and rearend lubricants will be brought up to temperature. It will take two more five-lap runs following the initial outing before we will be able to get meaningful tire temperatures.
After each of these runs, record the tire pressures and temperatures, tire sizes, shock travels at each corner, engine water and oil temperatures, and the number of laps run in each session. Make hard copy records of each as opposed to digital records (stored in the tire temperature/pressure box or a computer). It is fine to have digital records, but it's easy to lose digital information. Doing both, if possible, is the best way.
Once the driver is confident that the car is sound, longer and faster runs can be done. As you make your next series of runs, have the driver stay out at least 10 laps so that the tire temperatures will be sufficient to show how they are working. Unless the car has a serious handling problem, this should not be a problem. View the car from a high vantage point and note how the car looks and the position of the driver's hands in the middle of the turns.
Evaluation Time
Evaluate the tire cambers, pressures, and overall handling balance. Make quick adjustments to the front tire cambers and all four tire pressures if the temperatures dictate. The handling cannot be properly evaluated if these issues are not corrected right away. Do not make chassis adjustments until the tire issues have been corrected.
Excess driver steering input at mid-turn, inability to keep the car low in the turns, and a car that snaps loose coming off the turns are all indications of a tight setup. Have the driver run the turns at a speed lower than normal and note the position of his/her hands. Once the car is up to speed, the driver should again note where the hands are, and if the steering is significantly different, the car is either tight or loose.
Record the driver's and the crew's comments on the handling and engine performance. If the car is not neutral, now is the time to make changes to improve the handling while working to maintain a balanced setup.
There is a difference between handling balance and dynamic balance. The car is neutral when it is neither tight nor loose. Most cars can be easily adjusted to be neutral. This does make the car faster, but is not the goal. The car needs to be both neutral in handling and balanced in how the front suspension and rear suspension are working. When both ends of the car are working together, you will have a balanced car that is both fast and consistent.