Now it's time to adjust the Maximum Motorsports caster/camber plates. Move the main plate toward the firewall (green arrows), and you'll add positive camber. Moving the main plate toward the radiator (yellow arrows) adds negative camber. Use the top plates to move the top of the strut toward the outside of the car (red arrows) to add positive camber, or toward the inside of the car (blue arrows) for more negative camber. You can swap the top plates left to right to move your adjustment range more to the positive or the negative. These are in the positive position.
Maximum Recommendations
Street Driving
Camber can usually be set to -3/4 degree. Better cornering can be had with more negative camber, such as 1 degree or more, but at some point, tire wear will become uneven and excessive on the inside edges. In some situations, the wear might be excessive even at only 3/4 degree of negative camber. How negative the camber can be before poor tire wear begins is dependent on a number of factors: tire size or brand, the particular driver and driving technique, and the types of roads driven on. Someone who drives mostly on freeways will get better tire wear with less negative camber than someone who drives on twisty mountain roads. The primary focus on a street-driven car is generally to set camber to get the most tire longevity, not the ultimate cornering grip. Adjust camber to be as negative as the car will tolerate while still providing adequate tire life.
Toe will be set to a slight amount of toe-in, and the factory specification is fine. This keeps the car stable for easy street driving. An improper toe setting, whether toe-in or toe-out, will cause excessive tire wear. When diagnosing tire-wear problems, look at the toe setting-not just the camber setting.
The caster setting depends on the basic model. Fox-chassis Mustangs have different requirements than SN-95s. The '79-'93 Mustangs should have as much positive caster as possible, which is typically in the neighborhood of four degrees. With the '94-'04 Mustangs, there's enough adjustment range when fitted with MM caster/camber plates to have more caster than is desirable for a street-driven car. Usually increasing caster to a setting of about +4.5 degrees works well. Additional caster creates a problem with bumpsteer, as the steering arm on the spindle rises with increased positive caster. That raises the tie rod, altering the amount of bumpsteer. More caster would still be OK if you're willing to measure and adjust the bumpsteer.
At Inver Grove Ford, Dustin put the Cobra on the rack, which consists of a drive-on lift with set of turn plates that allows the wheels to turn. There's also a separate jack that lifts the front end so steering and suspension adjustments can be made without the car's weight on the front wheels.
On a street-driven car, it's common for alignment shops to adjust the passenger side to a slightly more positive setting than the driver side. A car tends to pull toward the side with less positive caster. By adjusting the caster so it has a slight pull to the left, the tendency for the car to be forced to the right by the crown of the road will be counteracted. Caster split-the difference in caster from one side to the other-of less than 1/2 degree isn't likely to be noticed by the driver, and yet it's enough to counteract most of the pull from the road crown.
The thing to keep in mind is that caster measurement is mostly an approximation; it's not directly measured to provide a definite, absolute number, as camber is. Caster measurement is basically an extrapolation made by measuring the difference in camber with the wheels steered first in one direction, then in the opposite direction. There are a lot of factors that can affect caster measurement, and therefore the resulting number. For example, any rake to the car will affect the caster measurement, as will changes in ride height. Probably the biggest variable is the competency of alignment technicians, and their proficiency in the use of the equipment. On any individual car, the more important thing is the change in caster from the stock setting that's made, not the final number.