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AUTOEXE Lower Arm Bar (Rear) for Mazda RX8 (Series 1 & 2, 2003-2012)

Reinforces rear lower-arm pivot mounts to limit toe change under cornering load, keeping rear geometry consistent for a settled, composed feel through corners.

Close underside view of red RX8 rear lower arm brace beside exhaust and suspension

Reviews from around the web

Independent reviews of this product gathered from other stores and owner communities.

The rear lower arm bar is very nice and strong. There are 4 pieces two triangular bars for the subframe and two smaller bars that strengthen the rear arm.

Overall I'm very happy with the bars. The quality of the autoexe bars are excellant and the packaging and handling of the bars are superb. I found my turn in using the autoexe bar was more responsive then my old Cusco lower arm. As well my rear is more stable when exiting out of corners. The best part about these bars is probably the front member brace and the triangualar rear brace that strengthen up the chassis. Because with my current suspension setup to the max and without my roll cage installed yet, my cars chassis is flexing from the pressure and stress buildup that I put on it at the track. For the price I'm very satisfied. Even though the price isn't cheap and in some cases you can buy a car, but the bars are definatley worth the money.

RX8 Upgrades Front AutoEXE Rotors , Pads and Lines
Now to eat , sleep and repeat on the rear
Should be able to out brake Clint Jenner at revival now

$300

An RX8 rear lower arm brace targets a specific weak point that upper chassis bracing cannot reach. Steel pipe construction reinforces the left and right lower suspension pivot mounts. These are the points where alignment change has the greatest influence on rear toe angle.

Cornering and acceleration loads cause those mounting areas to flex. That flex builds gradually through a corner. The rear end then starts to wander rather than hold its intended line. This AUTOEXE bar suppresses that deformation at the source.

AUTOEXE RX8 Rear Lower Arm Brace Key Features

  • Steel pipe construction reinforces the pivot fulcrum of the rear suspension directly, where chassis loads most affect toe angle.
  • Limiting alignment change at the suspension mounts produces an immediate sense of more secure steering, with greater accuracy through direction changes.
  • It suits all RX8 builds from 2003 to 2012, covering both generations. No geometry changes are required, and it causes no disruption to an existing setup.
  • In a staged chassis build, upper bracing delivers the most immediate turn-in improvement. This rear lower arm brace then addresses toe shift under load, a separate problem upper bracing cannot solve.
  • Finally, pairing this rear bar with the AUTOEXE MSE440 front equivalent completes the lower chassis package. The result is a car that feels composed and cohesive rather than simply stiffer.

For RX8 enthusiasts working through a staged chassis build, the order of attack matters. Upper bracing sharpens turn-in noticeably. Adding a rear lower arm brace then contributes the next layer: a rear end that tracks its line through the corner exit. It no longer drifts wide as forces peak.

The result is a car that feels tied together through sustained cornering loads, not nervous at the limit. It runs quieter and smoother once each mounting area is addressed in turn. That cohesion is what the owner-built SE3P chassis can achieve with a methodical approach.

The natural companion piece is the AUTOEXE Lower Arm Bar (Front), which brings the same pivot-mount reinforcement to the front suspension and completes the RX8 rear lower arm brace package end to end.

Owners who have not yet addressed upper chassis rigidity should start with the CUSCO Strut Brace Type OS (Front) with Brake Cylinder Stopper. Sharpening turn-in up front is exactly what this rear bar is built to complement. Learn more about the full chassis range at the AUTOEXE official site.

Reviews from around the web

Independent reviews of this product gathered from other stores and owner communities.

The rear lower arm bar is very nice and strong. There are 4 pieces two triangular bars for the subframe and two smaller bars that strengthen the rear arm.

Overall I'm very happy with the bars. The quality of the autoexe bars are excellant and the packaging and handling of the bars are superb. I found my turn in using the autoexe bar was more responsive then my old Cusco lower arm. As well my rear is more stable when exiting out of corners. The best part about these bars is probably the front member brace and the triangualar rear brace that strengthen up the chassis. Because with my current suspension setup to the max and without my roll cage installed yet, my cars chassis is flexing from the pressure and stress buildup that I put on it at the track. For the price I'm very satisfied. Even though the price isn't cheap and in some cases you can buy a car, but the bars are definatley worth the money.

RX8 Upgrades Front AutoEXE Rotors , Pads and Lines
Now to eat , sleep and repeat on the rear
Should be able to out brake Clint Jenner at revival now

Additional information

RX8 Model

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SKU AE-LABR-S1S2 Categories , Types , Brand:

Related RX8 Upgrades

This rear lower arm bar is one of the best Mazda RX-8 upgrades you can make to your Series 1 (2003-2008) or Series 2 (2009-2012). Rear suspension braces are among the top Aftermarket mods you can buy from AUTOEXE for owners who want better performance and reliability from their RX8. If you are looking for rx8 rear lower arm bar 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

Will this rear lower arm brace fit both Series 1 and Series 2 RX8 models?

Yes, the AUTOEXE Lower Arm Bar (Rear) fits all RX8 models built from 2003 to 2012, covering both Series 1 and Series 2 without any modification required to your existing suspension setup.

What problem does the rear lower arm brace actually solve on an RX8?

It limits toe variation at the rear lower-arm mounting points under cornering and acceleration loads. As rear loads build mid-corner, unchecked movement at those mounts causes gradual toe shift that makes the rear end feel imprecise or prone to wandering wide. This bar targets that specific mounting area directly.

How does this differ from a strut tower bar or rear upper cross-brace?

Strut tower bars and upper cross-members improve chassis response through direction changes, but they cannot reach the rear lower-arm mounting area where toe variation builds under load. The AUTOEXE rear lower arm brace works at a separate layer of the chassis, addressing what upper bracing leaves unresolved.

In what order should I fit chassis bracing to my RX8?

Upper front and rear bracing delivers the most immediately noticeable improvement in turn-in and direction-change response, so that is the recommended first step. The rear lower arm brace then adds the next layer by resolving the toe shift under load that upper bracing cannot address.

Is there a matching front lower arm bar that pairs with this rear brace?

Yes. The AUTOEXE Lower Arm Bar (Front) applies the same mounting-area reinforcement to the front suspension, completing the lower arm brace package front to rear. Running both together gives a cohesive, settled feel across the full chassis rather than addressing only one end.

Will adding this brace make the ride feel harsh or overly stiff?

No. The rear lower arm brace limits unwanted movement at the suspension mounting points rather than rigidly linking the chassis in a way that transmits harshness. The described effect is a rear end that feels quieter, smoother and less nervous, not simply stiffer.

Does fitting the AUTOEXE rear lower arm brace require any geometry changes or realignment afterwards?

No geometry changes are required for fitment. It is described as a non-disruptive addition to an existing setup, suitable for any RX8 from 2003 to 2012 without altering the current suspension geometry.