Circuit Sports Extended Upper Ball Joints – Mazda Miata NA (1990–1997)

The Circuit Sports Upper Ball Joints for the Mazda Miata NA (1990–1997) are a direct bolt-on replacement designed to increase negative camber by approximately -2 degrees, with an overall adjustment range of roughly -0.5° to -4°, depending on suspension setup.

Over time, the dust boots on OEM upper ball joints can deteriorate, allowing dirt and debris to enter the joint. This contamination can lead to clunking, vibration, reduced steering precision, and excessive tire wear. Circuit Sports upper ball joints are engineered as a high-quality replacement, offering improved suspension geometry, performance, and longevity.

Each unit is manufactured and assembled by an ISO9001:2000-certified manufacturer and features:

• Forged housing and ball stud

• High-quality rubber dust boot

• Oxidation- and corrosion-resistant silver zinc coating

Built to tight tolerances, these ball joints provide approximately 40% increased stiffness over OEM, resulting in improved steering feel, more consistent camber control, and enhanced durability under aggressive driving conditions.

The kit includes high-grade mounting hardware and cotter pins for a straightforward, direct installation.

Professional wheel alignment is highly recommended after installation. Minor toe adjustments may be required depending on ride height and alignment goals.

Sold as a pair (price includes two upper ball joints).