Race Car Quality Scailing For Beginners - Tech Talk

Now, The Car
Now that all the strings are straight and level across the tops of all the pads, re-measure your calibration weights on each scale to confirm that your readings have remained stable. If not, repeat the calibration and leveling process from a different point on your scaling box. If they are repeated, mark each scale for location and use it only at that location (right-front, left-rear, etc.) in the future, unless you are using less than four scales. If at some time in the future, you come to suspect that one scale may be operating improperly, weigh the car backward and compare the suspect scale's readings to your previous readings for that corner of the car.

Make your notes, take off the strings and remove the scales because it's finally time to get around to the race car. Roll it into position, jack it up, slide the scales with the necessary shims (or the wheel platforms if you are using less than four scale pads) back into their respective locations, and lower the car onto the scales. Again, just a little bit of change in the location of the tires can make a sizable difference in the weight readings, so pay close attention to getting the tires on the scales right where you marked them during the calibration step.

The only way you are going to be able to translate your scale results to on-track performance is if you weigh the car as you are going to race it. Top off all the fluids, especially the fuel tank, and get your driver or somebody who is the same size to sit in the driver's seat with his feet on the pedals and his hands on the wheel. Be sure you have your race tires on all four corners and be sure they are pumped up to racing pressure. Finally, disconnect any antiroll bars you might be using.

Settling the chassis is an important step to maintain the consistency of the results from weigh session to weigh session. After you have checked to make sure the springs are in their seats, have somebody push down and quickly release the front and rear of the car.

Taking Readings
Next, read the scales and determine where you are percentage-wise. Add all of the scale readings together and you'll have the overall weight. Total the left-side weights and divide by the overall total and you'll get the left-hand percentage. The sum of the two rears divided by the overall tally yields the rear percentage. Add the right front and the left rear (wedge weight) and divide it by the overall weight and you have the percentage of wedge.

So now that you have balanced the weight into a set of percentages you would like to try on the track, it's time to check the ride height. Take a measurement of the distance between the floor and the top of the scales and subtract that from the distance between the floor and the normal measuring point on the framerail. Adjust the jackscrews as necessary and recheck the weights. They'll change so keep massaging until both are where you need them.

When it all finally balances, reconnect the antiroll bars and set the bar preload. Note the changes in the scales so you can duplicate that change in the future as well, and you are off to the races.

After you have been to the track and made some changes, put the car back on the scales and see what you have done. Take copious notes and before you know it you will have a setup book worthy of a Winston Cup team and the confidence to use it.