Bumpsteer refers to the toe angle of the car changing as the suspension travels in it’s up and down motion. This is due to the tie rods traveling at a different rate than the control arms. This is compounded by a rough or imperfect road surface that will cause the suspension to react. The result is a car that feels like it changes directions as it hits these imperfections in the road. At best, bumpsteer is a nuisance. At its worse, it can be dangerous on rougher roads and higher speeds.
This is accentuated when the car is lowered and its “normal” ride height has already placed the tie rods and control arms in a much different position than the manufacturer intended. The fix for this is a bumpsteer kit, such as those offered by Steeda.
As you lower your car, you also change the camber angle of the front wheels. If this is left out of spec, it can dramatically affect tire wear. In some cases, all that’s needed is a trip to the alignment shop. The larger amount of lowering involved, however, the more you may find yourself needing to enlist the help of camber plates for your front shock towers. One benefit of aftermarket camber plates is that most will also facilitate the ability to adjust caster angle as well, should you desire to do so.
Keeping the lessened clearance in mind, is one of the most important aspects of lowering your Mustang. Many driveways and parking lots may make lowering your car an unrealistic upgrade. So you should think about places you visit on a regular basis such as stores and your job. Other things to consider are routine maintenance. Can you get a jack under the car to lift it when changing your oil, or will you also need to get some ramps to raise the car enough to use the jack? After considering all the potential issues, you may find that you want to lower a car a little less you had originally intended.
The roll center is found by using a pair of imaginary lines that would follow the control arms and intersect with one another. The goal of a perfect suspension is to keep this point and the center of gravity as close as possible. As you lower the car, this intersection point changes and alters the difference between these two points. The result can be increased body roll. The cure is a normally a thicker swaybar, however other options include ball joint and control arm relocation kits.
Depending upon the change in ride height and spring rate, you may want to investigate whether you need to replace the shocks and struts. The shocks and struts dampen the movement of the springs, helping to restore a more comfortable ride and keeping the suspension more predictable. With the myriad options of shocks and struts available, it’s a good idea to enlist the help of the manufacturer or vendor to properly match your springs with your shocks/struts if needed.