MX-5 NA Ultra Racing Rear Anti-Roll Bar

While the front sway bar handles turn-in and camber stability, the rear anti-roll bar is what dictates how your MX-5 rotates through a corner and puts power down on the exit. The factory NA rear bar (if your car even has one) is often too thin to cope with modern sticky tires, leading to a rear end that feels “lazy” to follow the front or prone to excessive lean that lifts the inside wheel.

The Ultra Racing Rear Sway Bar is the missing piece of the puzzle for a balanced chassis. By increasing the rear roll stiffness, we’re allowing the car to pivot more naturally around its center, reducing understeer and providing a more “telepathic” connection to the rear tires.

What’s inside the kit:

• 16 mm Solid Spring Steel Sway Bar – A calculated increase in diameter over the factory 11-12 mm bars.
  • Solid Core Construction: Provides consistent, linear resistance to body roll without the “yielding” feel of hollow bars.
  • Rotation Control: Specifically sized at 16 mm to improve rotation without making the rear end too “snappy” or prone to unpredictable oversteer.
  • Pro Tip: This sway bar is the perfect companion to the Ultra Racing 23 mm front bar, creating a front-to-rear stiffness ratio that maintains the MX-5’s neutral handling characteristics.

• Reinforced Rubber Mounting Bushings & Brackets – A complete set of hardware for a direct bolt-on installation.
  • Street-Friendly Performance: These bushings are designed to be stiffer than the soft factory rubber while still absorbing high-frequency road vibrations.
  • Low Maintenance: Unlike polyurethane, these reinforced rubber bushes don’t require regular re-greasing to stay silent.
  • Why they’re here: We’ve included these to ensure that the increased stiffness of the bar is transmitted directly to the chassis rather than being lost in tired, 30-year-old mounting points.

Key benefits:

• Neutral Handling: Reduces the car’s natural tendency to understeer, allowing for a more aggressive line through the apex.
• Flatter Cornering: Keeps the rear subframe level, ensuring the rear tires maintain a more consistent contact patch during hard acceleration out of corners.
• Improved Rotation: Makes the car feel more eager to “turn in” and rotate, particularly in tight, low-speed hairpins.
• Predictable Breakaway: Increases roll stiffness enough to be effective without sacrificing the progressive, easy-to-manage slide the NA is famous for.
• Durable Finish: Finished in Ultra Racing’s signature white powder coat for excellent corrosion resistance and easy visual inspections.

This kit is for you if:

• Your NA feels “tight” in the front but the rear still feels like it’s “wallowing” or slow to react.
• You want to tune the car’s balance to be more neutral or oversteer-biased.
• You are running a staggered tire setup or very sticky compounds and need more rear roll control.

This kit is NOT for you if:

• You are already struggling with oversteer: A stiffer rear bar will make the rear end lose grip sooner; address your alignment or front-end setup first.
• You are looking for maximum comfort: Stiffening either axle will result in a slight increase in “scramble” when hitting one-wheel bumps (like potholes).

Fits all 1989-1997 models – NA (Mk1).

Shipping worldwide.