Panhard arc
After lowering, manufacturers such as UMI and Spohn specifically recommend adjustable panhard capability to re-center the rear axle side-to-side.
SUSPENSION · 1993–2002 · LOWERING
Lowering Changes More Than Ride Height
Lowering can move the rear axle laterally, change control-arm geometry, reduce travel and create new exhaust/driveline clearance problems.
APPLICATION: Modified 1993–2002 Firebird / Formula / Trans Am. Exact installed springs, shocks, axle, torque arm, wheels and exhaust control.
Lower-control-arm angle
UMI's lowering packages pair relocation brackets with lowered cars to correct control-arm angle and improve the rear suspension's launch/traction geometry.
Clearance and travel
Lower ride height changes exhaust/crossmember clearance, bump-stop margin, shock travel and wheel/tire clearance. A part that clears at static ride height can still contact dynamically.
After lowering, verify
- Rear axle centered in the body at normal ride height.
- Control-arm/relocation geometry and fastener clearance through travel.
- Pinion/driveshaft relationship after torque-arm changes.
- Front alignment and bump-steer behavior.
- Exhaust, torque-arm crossmember, driveshaft loop and floor clearance.
- Tire clearance on both sides with suspension loaded and articulated.
FPV RULE
OBSERVE → MEASURE → ISOLATE → PROVE → REPAIR → VERIFY. Do not turn a symptom, DTC or catalog fitment label into a parts order.