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CUSCO Strut Brace Type OS (Rear) for Mazda RX8 (Series 1 & 2, 2003-2012)

Bolt-on rear tower brace that ties the chassis together for sharper, more predictable cornering on Series 2 cars.

Mazda RX8 rear strut brace fitted across luggage bay behind rear seats

$300

A Mazda RX8 rear strut brace targets one of the most accessible flex points on the chassis. Under cornering load, the rear suspension towers can shift relative to each other, allowing geometry to drift and blurring the car’s responses. This CUSCO Type OS brace links those towers rigidly. The result is a stable suspension platform and cleaner, more predictable rear-end behaviour through every bend and direction change.

In a staged chassis build, upper bracing at both ends is the natural first step. Front and rear tower bars tackle the most accessible flex points before progressing to underbody or lower reinforcement. This rear suspension brace slots precisely into that role. It pairs directly with the front equivalent to complete the upper chassis layer.

Mazda RX8 Rear Strut Brace Type OS Features

  • Oval-section aluminium bar delivers rigid rear tower support while keeping overall weight low.
  • It mounts directly to factory points, so the install is a true bolt-on fit with no body modification needed.
  • Series 2 specific geometry ensures a precise, rattle-free mount on 2009-2012 rear towers.
  • CUSCO’s blue-anodised end plates give the brace a purposeful, finished appearance in the rear cabin.
  • Finally, this RX8 rear tower bar is engineered in Japan by CUSCO, whose motorsport-derived catalogue has underpinned Japanese performance cars for decades.

For RX8 enthusiasts, the gain shows up at turn-in on a tight corner and through quick left-right transitions. The chassis feels more tied together, and suspension inputs translate into movement rather than disappearing into flex. Driver feedback sharpens noticeably, and the rear settles with more authority under braking.

Learn more about CUSCO’s engineering philosophy at the CUSCO official website. This Mazda RX8 rear strut brace pairs directly with the CUSCO Strut Brace Type OS (Front) with Brake Cylinder Stopper, which completes the upper chassis layer at the front towers and adds brake master cylinder bracing in one step.

Owners looking to extend the gains into the lower structure will find the AUTOEXE Lower Arm Bar (Front) a logical next move. For a more comprehensive suspension overhaul, the KTS SC Damper System Coilover Set works well alongside upper and lower bracing as a full chassis package.

Additional information

RX8 Model

SKU CU-RSB-S1S2 Category Types , Brand:

Related RX8 Upgrades

This ram air intake system is one of the best Mazda RX-8 upgrades you can make to your Series 2 (2009-2012). Ram air intake upgrades are among the top Aftermarket mods you can buy from CUSCO for owners who want better performance and reliability from their RX8. If you are looking for rx8 ram air intake for sale in Brisbane (QLD), Sydney (NSW), Melbourne (VIC), Canberra (ACT), Adelaide (SA), Darwin (NT) or Perth (WA), you’ll find high-quality Japanese Bracing upgrades at RX8 Upgrades.

Frequently Asked Questions

Does this CUSCO rear strut brace fit both Series 1 and Series 2 RX8s?

This Type OS rear strut brace is Series 2 specific, suited to the 2009-2012 rear tower geometry. If you have a Series 1 RX8, check whether CUSCO offers a separate rear brace for that body generation before purchasing.

Do I need to modify the body to fit this brace?

No body modification is required. The CUSCO Type OS rear strut brace mounts directly to factory points on the Series 2 RX8, making it a true bolt-on install.

What material is the bar made from, and how heavy is it?

The bar uses an oval-section aluminium construction, which keeps weight low while delivering rigid rear tower support. No specific weight figure is published for this brace.

What does a rear strut brace actually do for an RX8 on the road?

By linking the rear suspension towers rigidly, the brace prevents chassis flex from allowing the rear suspension geometry to shift under cornering load. The practical result is more stable and predictable rear response through bends, quick direction changes, and under braking.

Should I fit a front strut brace at the same time?

Pairing this rear brace with the CUSCO Strut Brace Type OS (Front) with Brake Cylinder Stopper completes the upper chassis bracing layer at both ends. Addressing both towers together gives the suspension a consistently stable platform and maximises the benefit of each brace.

What does the brace look like inside the rear cabin?

The CUSCO Type OS features blue-anodised end plates, giving the brace a purposeful, finished appearance where it sits visible in the rear cabin rather than looking like raw fabrication.

Is this brace suitable as part of a staged chassis build?

Yes. Upper tower bracing at both ends is the recommended first step in a staged chassis approach, tackling the most accessible flex points before moving to underbody or lower reinforcement. This rear brace fulfils that role, and the AUTOEXE Lower Arm Bar (Front) is a logical next step once the upper layer is complete.