I've read many articles on setting corner weights. They all seem a bit generic and don't offer specific advice for production based cars where you can't really get purpose built race car perfection. For what it's worth, this is my procedure for setting weights on a production based car with adjustable coilovers:
Due to driver weight, production cars usually weight more on the left side than the right. This cannot be adjusted out with weight jacking and should not be attempted. Trying to equalize cross weight will result in poor handling. The most important adjustment is to equalize the front to rear weight distribution on each side. This will result in equal understeer/ oversteer balance in right and left turns. Secondarily, the weight on each front wheel should be as close, right to left, as possible to maximizing braking performance. This will provide a greater improvement in lap times than equalizing rear weights. Here are the steps for measuring and adjusting:
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Weight scales must be exactly level with each other. Floor tiles can be used to adjust heights. A laser level works best to set levels.
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Blocks or ramps must be used so that the car can be rolled on and off the ramps. NEVER jack a car up to put it on scales. Due to friction in bushings, linkage, and shocks incorrect readings will result.
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Raise up the car or remove each wheel. Set the tire pressures to normal race pressures. Unless the tires are new, measure the circumference of each tire and adjust the air pressure to make sure right and left tires are the same diameter on each axle.
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Disconnect at least one side of both the front and rear sway bars. (Important)
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Before rolling the car onto the scales measure and set the desired ride height at each corner.
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Always roll the car and bounce the car for at least 20 feet after any adjustment and re-measure before moving on to the next step. Repeat adjustment if needed.
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To weigh the car it should be in “race trim” meaning race fuel and driver. Alignment should be close to race settings. Final alignment will be done after weight balance. Driver should be in the car for alignment as well.
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If possible, shocks should be disconnected or set to their softest setting if they are adjustable.
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Ensure that the car has been bounced and settled. Roll the car onto the scales and measure the starting static corner weight. Static weight can only be changed by physically moving weight around the car, not by spring adjustments.
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Record the weights of each corner and calculate the front to rear weight distribution for each side of the car. Cross weight is a calculation that is only useful for “wedge” adjustment for oval track racing.
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Determine how corner weights need to be adjusted to equalize the front to rear weight distribution on each side. Adjusting the spring perch to increase pressure on one corner will increase the weight pressure on the diagonally opposite corner.
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Choose to adjust the corner that will result in the pressure on each front wheel being the closest to equal side to side. It is better to make small adjustments at each wheel rather than a larger one at one wheel to minimize the change in ride height at each corner.
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It is important to roll the car off the scales, raise the car up to make any adjustments. Then drop the car down, roll and bounce, then roll back up onto the scales to recheck results. This can be time consuming and take several tries.
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After corner weights are set, sway bars can be reconnected. Adjust or shim the drop links to make sure that there is no static twist or torque on the bars (with the driver in the car!).
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Reconnect or readjust the shocks, if needed.
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Recheck the corner weights if the alignment changes significantly.
Finished! That was easy wasn’t it?
