SuperPro SPF1990K Rear Lower Outer Bush Kit for 90-05 Mazda MX-5 Miata NA/NB/NC

Vehicle Fitment

• 1990-2005 Mazda MX-5 Miata (NA chassis, 1990-1997)
• 1990-2005 Mazda MX-5 Miata (NB chassis, 1998-2005)

Fitment Notes

• Rear lower control arm, outer position only
• NC (2006+) is not covered by this fitment range - confirm chassis generation before ordering

Features

• SuperPro's iconic polyurethane compound replaces worn factory rubber for a direct OE-style fit
• Reduces control arm deflection for more consistent rear wheel alignment
• Improves handling precision and steering feedback during cornering
• Knurled bushing surface helps retain grease longer, reducing ongoing maintenance
• Engineered to balance increased durability with minimal added NVH (noise, vibration, harshness)
• Resists degradation from oils, road grime, and everyday wear better than rubber
• Suitable for street driving, autocross, and track use
• Backed by SuperPro's lifetime warranty on bushing products

Specifications

• Fitting Position: Rear, Lower Control Arm - Outer
• Bushing Material: Polyurethane
• Fitting Difficulty: Difficult
• Estimated Fitting Time: Approx. 3 hours (180 min)
• Axle Alignment Required: Yes
• Warranty: Lifetime (SPF bushing products)

Included Components

• Rear Lower Control Arm Bushings - Outer Position (quantity per SuperPro kit specification)

Product Description

The rear lower control arm on a Miata locates the rear wheel and plays a direct role in how the rear end tracks under cornering and braking. Over time, the factory rubber bushing at the outer mounting point wears and softens, letting the arm move more than it should and dulling the car's rear-end response. The SuperPro SPF1990K replaces this bushing with a polyurethane unit built to resist that kind of wear and hold its shape far longer.

Because this is the outer position of the rear lower arm, tightening it up has a direct effect on how precisely the rear wheel follows steering and throttle inputs - many owners pair this with the corresponding inner-position bushing (SPF1988K) for a complete rear lower control arm refresh. SuperPro's polyurethane formulation is engineered specifically to avoid the harsh ride and extra noise that cheaper polyurethane bushings can introduce.

This kit suits NA and NB Miata owners looking to tighten up rear suspension feel that's gone soft with age, whether the car is a daily driver, autocross regular, or track car. Installation is rated difficult and typically takes around three hours per side, and a rear axle alignment is required afterward to reset toe settings.