Upgrading the suspension on a Mercedes-AMG GT R is one of the most effective ways to sharpen its already impressive dynamics. H&R lowering springs offer a proven solution to lower the center of gravity, reduce body roll, and give the car a more aggressive stance—all while retaining the factory damping characteristics. This comprehensive guide walks you through the installation process, highlights the measurable performance gains, and covers the critical alignment and safety considerations that follow a spring swap.

Tools, Parts, and Preparation

Before you lift the car, gather everything you need. Having the correct tools on hand prevents delays and ensures the job is done safely. The following list includes the essentials plus a few recommended extras for a smoother install.

Essential Tools

  • Floor jack and two jack stands (rated for at least 3 tons each)
  • Metric socket set – 10mm, 13mm, 16mm, 18mm, 21mm are common on the GT R chassis
  • Torque wrench (capable of 15–150 Nm)
  • Spring compressor (manual or hydraulic – must be compatible with MacPherson strut designs)
  • Flathead screwdriver and trim removal tools for plastic fasteners
  • Breaker bar (½-inch drive) for stubborn bolts
  • Safety glasses and mechanic’s gloves
  • Impact wrench – speeds up lug nut and bolt removal
  • Penetrating oil (e.g., WD-40 Specialist) – apply to bolts the night before
  • Digital caliper – measure ride height before and after for documentation
  • Floor scales or corner-weight scales (if you plan to corner-balance)
  • New hardware kit – H&R often includes new bolts, but replacing strut-to-knuckle bolts is a good practice

Parts Required

  • H&R Lowering Springs (part number varies by year: typically 28828-1 for the 2018+ AMG GT R, but verify fitment)
  • Optional: new top strut mounts and bump stops if yours are worn

Pro tip: Work on a level concrete floor. Ramps can supplement jack stands for extra stability, but never rely solely on a jack when working under the vehicle.

Safety First – Critical Precautions

Springs are under extreme tension. A spring compressor failure can cause serious injury. Always read the compressor’s instructions and never exceed its rated load. The AMG GT R uses coil-over-style struts at the front and a separate spring/shock arrangement at the rear. Each corner requires careful handling.

  • Disconnect the battery negative terminal if working near electronic ride-height sensors (AMG GT R has sensors for headlight leveling and adaptive dampers).
  • Use jack stands placed at the designated lift points under the sills – never under control arms or the subframe.
  • Wear safety glasses at all times – a flying spring retainer can cause severe eye damage.

Removing the Factory Springs

Begin by loosening the lug nuts while the car is still on the ground (use the breaker bar). Then lift the car and secure it on jack stands. Remove the wheels and set them aside.

Front Suspension Disassembly

The front strut is a McPherson-type assembly. Accessing it requires removing the brake caliper (use a wire hanger to support it – do not let it hang by the hose), the ABS sensor clip, and the sway bar end link. Then unbolt the lower strut bolt (typically 18mm) and the three top mount nuts under the hood.

  • Mark the top mount position relative to the strut tower before removing – you’ll need it for reassembly.
  • Remove the strut assembly as a unit. Place it in a spring compressor and compress the spring only enough to relieve tension from the top mount.
  • Remove the top mount nut (usually 21mm) while holding the strut shaft with an Allen key.
  • Carefully decompress the spring and remove the old spring.

Rear Suspension Disassembly

The rear is a multi-link setup with the spring separate from the damper. You do not need a spring compressor for the rear if you unload the control arm properly.

  • Support the rear lower control arm with a jack. Compress the suspension slightly to relieve load on the spring.
  • Remove the lower shock bolt (16mm) and the upper shock bolt (accessible from inside the wheel well or trunk).
  • Lower the control arm slowly until the spring can be removed by hand. Watch for rubber isolators – they can stick to the spring.
  • Inspect all bump stops and dust boots. Replace if cracked or torn.

Installing H&R Lowering Springs

Front Installation

  • Compress the new H&R spring to the same free height as the original compressed length (measure using the old spring as a reference).
  • Place the spring into the strut with the correct orientation (H&R springs are usually marked “top” or with a colored stripe).
  • Install the top mount, new bearing if supplied, and nut. Torque the top nut to 35–45 Nm while holding the shaft.
  • Decompress the spring and reinstall the strut assembly. Tighten the top mount nuts to 25 Nm and the lower strut bolt to 80 Nm (final torque with vehicle on ground).
  • Reattach the sway bar end link and brake caliper. Torque caliper bolts to 30 Nm.

Rear Installation

  • Insert the new rear spring into the lower control arm pocket. Ensure the rubber isolator is seated correctly.
  • Use the jack to slowly raise the control arm until you can align the shock absorber.
  • Install the shock bolts – upper first, then lower. Torque to 50 Nm (upper) and 70 Nm (lower).
  • Reattach any wiring clips or sensor brackets that were moved.

Reassembly and Initial Torque

Reinstall the wheels and hand-tighten the lug nuts. Lower the car to the ground with the suspension under load (wheels on the ground). Then torque the lug nuts to 110 Nm in a star pattern. Important: All suspension bolts must be torqued at ride height – meaning the car is on the ground with its full weight. This prevents bushing bind and premature wear.

Drive the car around the block gently to settle the suspension. Then re-torque all suspension bolts (lower strut bolts, control arm pivot bolts, and sway bar links) to the manufacturer’s specifications listed in the chart below.

Common Torque Specifications (AMG GT R)

  • Strut-to-knuckle bolt: 80 Nm + 90° (angle tighten)
  • Front top mount nuts: 25 Nm
  • Rear shock upper: 50 Nm
  • Rear shock lower: 70 Nm
  • Sway bar end link: 40 Nm
  • Lug nuts: 110 Nm

Always consult the latest service manual for your model year. The above values are typical for the GT R but may vary.

Performance Gains – Measured and Felt

H&R specifies a 25–35 mm front drop and 20–30 mm rear drop for the AMG GT R, depending on the variant. Combined with a progressive spring rate, the immediate improvements are:

  • Reduced body roll: The lower center of gravity and stiffer spring rate cut lateral weight transfer by 20–30 percent during aggressive turns.
  • Improved turn-in response: Less suspension deflection under braking and initial steering input makes the front end feel sharper.
  • Better traction under acceleration: The rear suspension geometry becomes more favorable, reducing wheel hop.
  • Visually aggressive stance: The wheel gap is nearly filled, giving the car a “track-ready” look.

For reference, owners on forums report a 0.2–0.3 second improvement on a 200-foot skidpad (lateral g increases from ~1.20g to ~1.25g) and 1–2 seconds faster lap times on a 2-mile road course, though driver skill is a larger factor.

Ride Quality and Daily Drivability

The AMG GT R already has firm Adaptive Sports Suspension. H&R springs are designed to work with the factory dampers. On Comfort mode, the ride remains composed – stiffer than stock but not harsh. On Sport+ mode, the harshness increases noticeably over broken pavement. Drivers who regularly track the car will appreciate the predictability, but daily commuters may find the rebound slightly too aggressive.

If you want to retain more comfort, consider pairing the springs with aftermarket adjustable dampers (e.g., KW or Bilstein).

Critical: Alignment and Geometry Changes

Lowering the GT R changes the suspension geometry significantly. The front gains negative camber (approximately -0.5° to -0.8° more) and toe-out increases. The rear gains camber as well. Without a proper alignment, tire wear will be uneven and handling will be unpredictable.

  • Front camber: -2.2° to -2.5°
  • Front toe: 0.05° toe-in per side (to counteract toe-out from lowering)
  • Rear camber: -1.8° to -2.0°
  • Rear toe: 0.10° toe-in per side (total 0.20°)

Note: If you cannot achieve the desired camber with factory adjustment, you may need camber plates (front) or eccentric bushings (rear). H&R’s geometry correction kits are available. Many AMG specialists, such as RENNtech, offer alignment packages tailored for lowered GT Rs.

Final Checks and Break-In

After alignment, take the car for a longer test drive – at least 30 minutes on mixed roads. Listen for clunking (loose bolts) or rubbing (tires contacting fender liners or the inner wheel well). Re-torque all lower suspension bolts after 100 miles. Check the ride height – it may settle another 3–5 mm after the first few heat cycles.

Document the final measurement from the center of the wheel to the fender edge for future reference. Consider a camber and toe recheck after 500 miles.

Common Mistakes to Avoid

  • Not marking the top mount position – leads to misaligned front strut, causing noise and premature wear.
  • Torquing bolts with the car in the air – always torque at ride height.
  • Reusing old strut bolts – many are stretch bolts and must be replaced.
  • Skipping the alignment – the car will pull, tires will wear out, and the increased toe-out can cause instability under hard braking.
  • Ignoring the headlight leveling system – the GT R has adaptive headlights; after lowering, you must recalibrate the sensor linkage to avoid blinding oncoming traffic.

Where to Buy H&R Springs and Additional Resources

Purchase directly from H&R’s official website or through authorized distributors like Tire Rack (they list H&R springs with verified fitment). For community support, join the Mercedes-Benz World AMG GT forum – members share installation tips, alignment specs, and before/after photos.

Conclusion

Installing H&R lowering springs on your Mercedes-AMG GT R is a rewarding upgrade that sharpens handling, improves turn-in, and transforms the car’s stance. While the installation process is straightforward for an experienced DIYer, attention to detail – especially torque procedures and alignment – is essential to unlock the full performance potential. With the right preparation and follow-through, you’ll enjoy a noticeably more capable track car that still retains everyday usability.