There is a correct amount...
There is a correct amount of cross-weight percentage for every combination of setup and weight distribution for your car. If your car needs 51 percent, the car will be tight if you run 52 or 53 percent. There is no need to change springs to try to loosen the car. You need to lower the cross-weight percentage by taking cross or wedge out of the car. The correct procedure is to balance the car with cross and then read the left-side tires. If the left front and left rear do not match tire temperatures, start changing spring rates, moment centers, etc. to balance the car. As the balance is corrected, the crossweight percentage must change with the other changes to maintain the handling balance.
8. Racetrack Transition - The shape of the racetrack can affect how the car is balanced when exiting the turns. If the transition is abrupt and the top of the track drops to match the inside edge elevation, the right-front will follow the drop-off and unload the left-rear wheel. Shock rebound rates need to be adjusted to allow the left-rear tire to stay in contact with the racing surface.
If the left-rear shock has too much rebound, that tire will lose a lot of weight and not be able to provide traction. The right-rear tire will be the only one trying to accelerate the car and it will spin. Decrease the amount of rebound in the left-rear shock and/or soften the rebound in the right-front shock to help this situation.
9. Excess Rear Stagger - Every race car needs a certain amount of tire stagger (tire size difference in the rear tires to compensate for the turn radius so the rear wheel rpm will be equal at mid-turn) and no more or less. Excess stagger should never be used as a crutch to help make the car turn in the middle or while under power if it is tight. Doing this will probably make the car loose off the turns while under power.
Stagger only affects mid-turn handling if the car has a locked rear differential or a Posi-traction type of rear differential. With a Detroit locker, one of the axles (usually the left side) will be unlocked going in and through the middle and lock back up on exit while under power. So, with this style of rear end, stagger should match the radius of the turn where the car is starting to accelerate.
Many racers could say they wished they had this problem, but nonetheless, it does exist. This condition is many times tied to a geometry problem or possibly a shock package mismatch. It hurts our performance because as we accelerate off the corner, we might need to eventually lift to avoid the outside wall if the push is severe enough.
The front mounting bracket...
The front mounting bracket on a three-link rear suspension is adjustable to allow the team to change the angle of the trailing arm. The driver can feel small changes to the height of the front of the trailing arm.
If we are racing someone and get under them coming out of the turns, we would most likely be forced to lift to keep from pushing up into the outside car. Many cars have been taken out because the inside car did not lift when they should have. Here are some common reasons why the car might be tight on exit off the corners.
1.Front Shock Compression Rates - If the right-front shock is too stiff on rebound or the left-rear shock is too soft on compression, the right-front corner of the car will lose weight as the car accelerates, causing the left rear to also lose weight. The result is more weight distributed to the left front and right rear, which reduces the crossweight percent. This will obviously make the car loose initially as the car starts to accelerate.
2.Rear Spring Rates - The rear spring rate combination could affect the car to make it tight off the corners. Excess rear spring rate split with the right-rear spring rate less than the left-rear spring rate would make the car very tight off the corner while under power. In most cases, reduce the spring split until the desired affect is less than needed and go back up to the next level. If you have a 25-pound split in the rear springs, try a 15-pound split and if that produces enough bite, leave it there. The car must be neutral off the corners so that we can maneuver around other cars in the race.
3. Rear Steer - A small adjustment to the geometry of the rear suspension can reduce the degree of rear steer to make the car more neutral while under power. If the car squats as power is applied, it is possible that the added movement is making too much rear steer to the left, which tightens the car considerably.
With three-link rear suspensions, the arms are fairly short and a 1/4-inch height difference at the front of the arms can be felt by the driver. A 1/2-inch change can make the car undriveable. Make height changes to your trailing arms in small increments.