Introduction

The NB Miata (1999–2005) is already celebrated for its balanced chassis and responsive handling, but even the best factory suspension can benefit from an upgrade as the miles pile up. Installing a Mazdaspeed shock absorber kit is one of the most effective ways to restore sharp turn-in, reduce body roll, and improve ride comfort on rough pavement. Designed as a direct factory upgrade, the Mazdaspeed kit features valving and damping spec’d specifically for the NB chassis, giving you sportier performance without the harshness of many aftermarket coil-overs.

In this comprehensive walkthrough, you’ll learn how to install the front and rear Mazdaspeed shock absorber kits on your NB Miata. Each step includes fastener sizes, torque specifications, and safety tips to ensure a professional result. Whether you’re a seasoned DIYer or tackling suspension work for the first time, this guide will help you complete the job with confidence.

Tools and Materials Needed

Having the right tools on hand before you start will keep the installation moving smoothly. Gather the following:

Required Tools

  • Mazdaspeed shock absorber kit (front and rear, if replacing all four)
  • Floor jack and two sturdy jack stands (or four for a full all-at-once lift)
  • Socket set (metric sizes: 10 mm, 12 mm, 14 mm, 17 mm, 19 mm, 21 mm)
  • Wrench set (combination wrenches in same sizes)
  • Torque wrench (ft-lb and in-lb ranges)
  • Breaker bar (for stubborn bolts)
  • Spring compressor (manual or hydraulic, essential for safely swapping springs)
  • Flathead and Phillips screwdrivers
  • Hammer (light, for persuading parts)
  • Pry bar or large flathead
  • Penetrating oil (WD-40 or PB Blaster)
  • Wood block or jack pad adapter (to protect the chassis pinch welds)
  • Impact wrench (saves time on lug nuts and large bolts)
  • Bottle jack (for fine height adjustments under the control arm)
  • Feeler gauge set (if you plan to check alignment after installation)
  • Thread-locker (medium strength, e.g., Loctite 242)
  • Anti-seize compound (for hardware that will be reused)
  • Work gloves and safety glasses
  • Digital camera or phone (to document disassembly)

Safety First

Suspension components are under extreme tension, especially coil springs. Never attempt to remove a spring without a proper spring compressor. A misstep can release hundreds of pounds of stored energy, causing serious injury. Always support the vehicle on jack stands rated for the Miata’s weight (about 2,400 lbs) and chock the wheels that remain on the ground. Work on a level surface, and never place any body part under the car unless it is securely supported.

Preparation

Park the Miata on a flat, hard surface. If the car has been driven recently, allow the exhaust and brakes to cool. Remove the spare tire, floor mats, and any loose items from the trunk and cabin that could shift while the car is raised. Loosen the lug nuts on all four wheels (but do not remove them) before lifting the car – this is much easier with the wheels on the ground. Give each bolt a light spray of penetrating oil a few hours before you start to prevent rounding.

If you are replacing all four shocks and do not own four jack stands, it is safe to work one axle at a time. However, raising both front and rear simultaneously (with four stands) can speed the job and simplify bleeding the braking system if you also disconnect brake lines (not required for shock removal).

Step 1: Lift and Support the Vehicle

For the front suspension, position the floor jack under the front crossmember (the subframe) between the control arms. Raise the car until the front wheels are off the ground, then place jack stands under the front frame rails – one on each side, near the pinch weld jacking points. Lower the jack slightly so the car rests fully on the stands. Give the car a gentle shake to confirm stability.

Repeat the same process at the rear, lifting by the differential housing (not the aluminum pumpkin) or by the rear subframe. Place stands under the rear frame rails or designated rear lift points.

Step 2: Remove the Front Wheels

Using a socket and breaker bar (or impact gun), remove the lug nuts you loosened earlier. Pull the wheel straight off the hub and set it aside, wheel face up. If the wheel is stuck, tap the tire sidewall with a rubber mallet or kick it from the back. Be careful not to damage the brake rotor or dust shield.

Step 3: Disconnect the Front Anti‑Roll Bar (Sway Bar)

The sway bar end links can interfere with lower shock bolt removal. Using a 14 mm socket and wrench, remove the nut from each front end link, then withdraw the bolt. If the ball joint spins, use an Allen key on the internal hex if present; otherwise, use a second wrench on the flat sides of the link. Remove the end link from the lower control arm and let the sway bar hang free.

Step 4: Remove the Front Shock Assembly

4a. Loosen the Top Mount Nuts (Engine Bay Access)

Open the hood. On top of each front shock tower, you’ll see three 12 mm nuts holding the upper mount to the chassis. Do not remove them yet – just break them loose with a wrench or socket while the car is raised and the shock is still under slight compression. This saves you from fighting a spinning shaft later.

4b. Remove the Lower Shock Bolt

At the bottom of the shock, there is a single through-bolt (17 mm head) that connects the shock fork to the lower control arm. Use a wrench on the nut side and a socket on the bolt head. Remove the bolt and the nut. If the bolt is seized, apply penetrating oil and let it soak. You may need to pry the fork slightly with a pry bar to free the bolt.

4c. Remove the Upper Mount Nuts

Now go back under the hood and remove the three 12 mm nuts holding the top mount. Support the shock assembly from below as you remove the last nut. The entire shock/spring assembly will drop down. Guide it out through the lower control arm opening. Be careful not to scratch the shock body on the control arm or brake lines.

Step 5: Disassemble and Reassemble the Front Shock/Spring

⚠️ Critical safety step: You must use a spring compressor to remove the coil spring from the old shock and transfer it to the new Mazdaspeed shock. Do not attempt to dismantle the assembly without one.

5a. Compress the Spring

Place the shock assembly in the spring compressor, following the manufacturer’s instructions. Compress the spring evenly until it is loose enough to remove the upper mount and bearing. For the NB Miata, the spring seat is not adjustable (the shock body has a fixed lower perch), so the spring is simply captured between the lower perch and the upper mount.

5b. Remove the Upper Mount & Bearing

With the spring compressed, remove the center nut (14 mm) that secures the shock rod to the upper mount. Hold the shock rod from turning with an Allen key or flathead screwdriver (depending on the shock design) while you turn the nut. Remove the nut, washer, then lift off the upper mount, rubber insulator, and upper spring seat. Carefully release the spring pressure by loosening the spring compressor slowly and evenly.

5c. Install the New Mazdaspeed Shock

Compress the new Mazdaspeed shock’s piston rod fully – it will extend on its own once you release it. Place the lower spring insulator (if removed) and the spring onto the lower perch. Ensure the end of the spring coil seats correctly in the groove. Now compress the spring again with the compressor, slide on the upper spring seat, rubber insulator, and the upper mount. Install the washer and center nut. Torque the center nut to 22–28 ft‑lb (follow Mazdaspeed specs if provided; otherwise use 25 ft‑lb). Remove the spring compressor.

Pro tip: Before final torque, align the upper mount’s studs with the orientation you need for installation. The three studs are asymmetrical – note the positioning relative to the lower shock fork. Typically, the fork should point forward (toward the front bumper) and the mount studs should position one stud toward the firewall and two toward the fender. Refer to photos of your original assembly if you didn’t mark it.

Step 6: Install the New Front Shock Assemblies

With the reassembled shock/spring unit ready, compress the spring slightly with the compressor (or use a tie‑down strap) to allow the assembly to fit into the wheel well. Guide the top mount studs up through the three holes in the shock tower. Hand-tighten the three 12 mm nuts from the engine bay. Remove the spring compressor or strap.

Now align the lower shock fork with the lower control arm mounting hole. Insert the 17 mm bolt and hand-tighten the nut. Do not torque any bolts yet – you need the bushings to settle at ride height.

Once both front shocks are in place, lower the car onto the ground or onto ramps. With the suspension under load, torque the upper mount nuts to 14–18 ft‑lb and the lower shock bolt to 50–60 ft‑lb. Reattach the sway bar end links and torque them to 30–40 ft‑lb.

Reinstall the front wheels, hand-tighten lug nuts, then lower the car completely. Torque the lug nuts to 65–80 ft‑lb in a star pattern.

Step 7: Rear Suspension Removal and Installation

The rear shock absorber removal is similar but requires a few extra steps because the shock is mounted separately from the spring on the NB Miata. The spring is not part of the shock assembly, so you do not need a spring compressor for the rear (the spring remains aboard the car).

7a. Access and Preparation

Lift the rear of the car and remove the rear wheels (refer to Steps 1–2). Inside the trunk, you’ll find the upper shock mount – there are two 12 mm nuts accessible after removing the plastic trunk liners (pull back the carpet and unscrew the plastic trim pieces).

7b. Remove the Upper Mount Nuts

From inside the trunk, use a 12 mm socket and wrench to remove the two nuts securing the top of the shock to the body. Do not remove the studs from the shock itself.

7c. Remove the Lower Shock Bolt

On the lower control arm, there is a 17 mm bolt securing the shock eye to the arm. Remove the nut and bolt. The rear shock is now free and can be withdrawn through the lower control arm area.

7d. Install New Rear Mazdaspeed Shock

Slide the new shock into position. First, attach the top mount to the studs in the trunk, hand-tightening the two nuts. Then align the lower eye with the control arm bracket, insert the 17 mm bolt, and hand-tighten the nut. Do not fully torque until the suspension is loaded.

Lower the car onto the ground or ramps. With the suspension settled, torque the upper mount nuts to 14–18 ft‑lb and the lower bolt to 50–60 ft‑lb. Reinstall the trunk liners.

Step 8: Post‑Installation Alignment

Replacing shocks can alter the vehicle’s ride height slightly, especially if your old shocks were worn. This changes the suspension geometry and can affect toe, camber, and caster. After the installation, have a professional alignment performed. Before going to the shop, drive the car for about 50 miles to allow the new shocks and bushings to settle. Flyin’ Miata’s recommended alignment specs are an excellent starting point for spirited street driving: -1.0° camber front, -1.5° camber rear, zero toe, and 5.0° caster.

If you plan to lower the car with aftermarket springs, you’ll need a separate spring installation and a new alignment afterward.

Step 9: Test Drive and Break‑In

Take your Miata for a gentle test drive on familiar roads. Listen for any clunks or rattles, and check that the steering feels centered and responsive. Perform a few low-speed turns to ensure the suspension cycles smoothly. If you hear a metallic noise from the front, double-check that the upper mount nuts are tight and that the spring is seated correctly.

For the first 500 miles, avoid aggressive cornering or hitting large potholes. This allows the new seals and bushings to wear in properly. After that period, re‑torque all the suspension bolts – they can settle slightly as the components seat.

Final Thoughts

Installing a Mazdaspeed shock absorber kit is one of the most rewarding upgrades you can make to your NB Miata. The improved damping control transforms the car’s composure on twisty roads and daily commutes alike. With careful attention to torque specs and a spring compressor for the front, this project is well within the reach of a capable home mechanic. For those looking to further sharpen the chassis, consider pairing the shocks with uprated sway bars and a performance alignment. For more detailed community wisdom, the Miata.net Suspension forum is an invaluable resource.

Remember to recycle your old shocks responsibly – many auto parts stores accept used suspension components. Enjoy the new feel of your Mazdaspeed‑equipped Miata, and happy driving!