Trailing Arms for Lowered Challengers: Do You Need Them?

What Are Trailing Arms?

The Challenger's rear suspension uses a multi-link setup where trailing arms connect the rear axle/differential housing to the chassis. These arms control fore-aft positioning of the rear axle and, critically, the pinion angle — the angle at which the driveshaft meets the differential input.

Stock trailing arms are fixed length, designed to maintain correct geometry at the factory ride height.

The Pinion Angle Problem

When you lower the Challenger significantly (more than 1.5 inches), the rear axle's position changes relative to the chassis. The fixed-length trailing arms now hold the differential at a different angle than stock — the pinion angle increases.

Effects of incorrect pinion angle:

• Vibration at certain speeds (driveline vibration that can be mistaken for tire or driveshaft balance issues)
• U-joint wear at an accelerated rate
• Reduced power transfer efficiency through the driveline
• Potential for binding or clunking in the drivetrain under hard acceleration

When You Need Adjustable Trailing Arms

Under 1 inch of drop: Factory geometry remains close enough to spec. Stock trailing arms are fine.

1 to 1.5 inches of drop: Worth checking pinion angle, but many builds at this height are fine with stock arms.

More than 1.5 inches of drop: Adjustable trailing arms are strongly recommended. The geometry correction they provide eliminates vibration and protects the driveline.

Adjustable Trailing Arm Options

QA1 Adjustable Rear Trailing Arms: One of the most popular options. Rod-end (Heim joint) construction allows precise length adjustment to correct pinion angle to factory spec regardless of ride height. ~$400–$600/pair.

UMI Performance Trailing Arms: High-quality option with adjustable geometry. ~$350–$500/pair.

BMR Suspension: Adjustable units with multiple configurations available.

How to Set Pinion Angle

Target pinion angle depends on your driveshaft angle — ideally both U-joints are at equal and opposite angles to cancel vibration.

General target: The pinion angle should be 1–3 degrees below horizontal (pointing slightly downward toward the front of the car) to account for the driveshaft angle from transmission output.

With the car at ride height on level ground, a digital angle gauge on the differential yoke gives you the current pinion angle. Adjust trailing arm length until you reach the target.

Most builds with 1.5–2" drops need to shorten the trailing arms by 3/8"–3/4" to restore correct geometry. Make adjustments in small increments, then drive and check for vibration before finalizing.