Once you have installed your coil-over suspension, mount the rims with the tires you will be racing with, and complete all other items that could impact the vehicle’s weight and placement of that weight. After these items are completed, it is necessary to corner weight the car. By changing the weight distribution on the car, you affect the way your car will behave when cornering. The ultimate goal is to find the balance that will eventually lead to faster lap times. When looking at corner weighting, the cross weight (diagonal weight) is the most important component. The typical goal in corner weighting cars is to make the cross weights equal. Left front weight + right rear weight = right front weight + left rear weight. Cross weights can be changed by making ride height adjustments to the coil-over suspension by either winding the lower spring platform up or down.
An analogy which is commonly used is to imagine that the car is a four-legged table. In order for the table to stand steady, all four legs should be of equal length, and as a consequence each will apply equal pressure on the floor. If one leg is longer or shorter than the others, the table will rock and thus be unstable. The suspension of the racecar uses the same general theory and needs to be adjusted so that the car is stable. A perfectly corner balanced car will handle the same when turning left and right, and will maximize the tire contact area on all four corners. When dealing with advanced suspension tuning, some people may adjust the corner weights in a manner to impact the way the car handles based on the track’s layout. This approach is commonly used in oval track racing. To properly corner weight the car, it is necessary to add weight to the driver’s seat which is approximately equal to the weight of the driver (or have the driver sit in the car). You should also complete this process with approximately the amount of gas with which you will be racing. A good starting point would be ¼ – ½ tank of gas. Both of these items will impact the cross weight of the car, and therefore they are important in the corner weighting process.
Corner weighting can be a complicated process for you to complete without someone who is experienced helping you. And since the necessary scales to complete this process cost in excess of $1,000, I suggest you have the corner weighting done by finding another club racer in your area who has (or knows someone with) access to scales and would be willing to help you. Or use an automotive tuning shop. Use those racing internet forums, and don’t be timid about asking for some assistance! Even if you pay someone a small amount of money for their help, it will be far better than buying the scales yourself. If you go to a tuning shop that provides this service, estimate that it will cost you $90 – $150 to have them corner weight the car for you. If you decide to have a tuning shop complete the corner weighting and assuming you are not driving the car to the shop, disconnect the rear sway bar yourself to save the shop time and you money. Tell the shop you will be disconnecting the rear sway bar when obtaining the estimate.
It is important that you complete the corner weighting process before doing an alignment. Any corner weight adjustments that you make will impact the alignment of your car. If you align your car prior to doing the corner weights, it will be necessary to verify the alignment again after the corner weighting is completed.