Corner Balancing PDF Print E-mail
Written by Ken Huey   
Saturday, 17 April 2010 07:59
Article Index
Corner Balancing
Adjusting Corner Weight
Adjusting Sway bar Preload
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Optimum corner weight

Preparation to weighing your car

  • Set tire pressures.
  • Disconnect front and rear sway bars.  You only need to disconnect from one side.
  • Decide if you want to measure with fuel weight at the beginning of a race, end of race or average between the two and add/remove fuel.
  • If you're running a cool shirt system put in the water weight into the cooler.
  • Put in the driver weight on the race seat, preferably the driver with full racing gear (suit, helmet, HANS, etc).
  • Measure and note ride height on all corners.

Weighing the car

  • Bounce the car at each corner to free any suspension binding and roll the car onto the scales.
  • We also tried putting the car on a two post lift and lowering the car onto the scales, bouncing the car at each corner and the results were the same.
  • Note corner weights.

You can enter corner weights here http://944spec.org/cornerbalance to solve for optimum cross weights. It will present a screen for you to enter your corner weights.

input screen

In this example we enter the values of 706 for the left front, 609 for the right front, 650 for the left rear, 645 for the right rear and then click on the CALCULATE OPTIMUM CORNER WEIGHTS button.  It will then output a screen similar to the picture below.

Results

Let's look at the left hand image (current corner weights) a little more closely.

Current Weight

You'll notice in this example that there is a 92 lbs difference between the Right Front + Left Rear cross weight vs. the Left Front + Right Rear cross weight.   This would make handling characteristics between left and right turns different, i.e.- this car might have a slight oversteer on left hand turns and a slight understeer on right hand turns.  It would be nice to get the cross weights as close as possible to keep handling balance similar between left and right turns.

You'll also notice our cars are very well balance front/rear.   The left side weight is heavier because we have the weight of the driver, the race seat, harnesses, etc. on the left side.   If you are light enough to be able to add ballast to the right side then do it for better left/right static weight balance. It would be ideal to get the left side static weight to 50% by taking out weight on the left side and/or adding ballast to the right side but that would be near impossible given the limits of our class rules since we also want to be as light as possible and close to the 2600 lb. minimum class weight limit with driver.   The best we can do is solve for cross weight.