When we change the front-to-rear percentage of total weight in the car, the crossweight ne
To stay neutral in handling, the required crossweight also needs to come down. Since it cannot change, the car will become tighter by having too much crossweight percentage as the lap times continue to fall off. One advantage of a balanced setup is that lap times stay more consistent, hence less change in the g-forces, as well as the required crossweight, and the more neutral the car remains.
* Lap times fall off considerably after 20 or so laps, while the leaders stay consistent.
* The RF tire shows excessive heat and wear compared to the other tires.
* The LF tire shows considerably less heat and wear than the other tires.
* The RR tire shows extreme heat and wear from spinning off the turns.
* The driver uses excess steering input at mid-turn compared to faster cars.
* The car "snaps" loose just when you get into the throttle.
As you make changes to make the car more balanced, the crossweight percentage will need to increase to keep up. If you raise the rear Panhard bar or stiffen the RR spring to reduce the rear roll angle to match the front, the car will become loose if you do not also increase the crossweight.
The process of balancing the car involves making the LF tire work harder. As that happens, the car will turn better with more traction available up front, meaning that we must also tighten the car with crossweight. Too many teams make adjustments that make the car more balanced, only to back off because the car gets too loose.
Pro-4 race cars are real race cars. They have all of the adjustments of the big Late Model
* Do weigh your car with the driver to know your exact weight distribution.
* Do level your scales, roll the car to take out all binding in the control arms, air up the tires to race pressures, and add all fluids, etc. before you measure the weights.
* Do make changes to the crossweight in the shop to know how much difference a turn of the screw or ring makes in the crossweight percentage.
* Do change all four corners when making changes to the crossweight percentage to maintain the correct ride heights. To put cross in, put turns into RF and LR springs and take turns out of the LF and RR springs. The opposite takes cross out.
* Do make records of your weights. Use the weights taken on racetrack scales for reference only. Do not ever change your crossweight to match the track scales.
* Don't build your setup around a particular crossweight percentage just because you have always run that number. Be open minded in order to find a better combination if that is what you need.
* Don't guess at the crossweight percentage in your car. The old way of jacking up the rear end with a large socket between the jack and the rear differential pumpkin and seeing how far off the ground the RR tire is when the LR tire is just touching is way out of date.
* Don't run the high crossweight range on high-banked tracks unless the banking falls off abruptly and there is a problem getting traction off the corners. And don't try to run the low range on the flatter tracks with bite-off problems, like I did at one time. That is how I learned about the different ranges.
* Don't move weight around in the car to effect changes to the crossweight percentage. Move the weight jacking devices or shim the springs in a stocker.
* Don't try to match your crossweight to a competitor that is running well. His overall weight distribution and setup may be different than yours, especially the front-to-rear percentage of weight. These setup components all work in combination, and each car's combination is necessarily different.
It has been said that knowledge is power, and as we all know, it can also mean speed. Knowing your weights is a part of that bundle of information you will need about your car in order to be competitive. Don't be shy about experimenting with items such as weight distribution, and by all means, think outside the box.
Once you find that perfect combination, you won't share it, just as no one shared with you. Then you'll know why it takes so long to be competitive. You must reach the point where you quit listening to your competitors and start thinking for yourself, no matter how long you've been racing.