Porsche 911 (996), Boxster (986 & 987), Cayman (987) Rear Sway Bar Bushing - 18.5 mm
Porsche Suspension Bushings by PowerFlex
Let’s face it, suspension bushings on a Porsche can endure high stress, lateral loads, torsional twist, and thermal cycling, often in harsh conditions with very little maintenance or lubrication. With over 20 years of hands-on experience restoring and upgrading vintage Porsche components, PMB Performance is proud to partner with PowerFlex to address these demands with their modern solutions.
Porsche 911 (996), Boxster (986 & 987), Cayman (987) Rear Sway Bar Bushing - 18.5 mm
The Porsche 911 (996) from 1998-2004, along with the Boxster (986: 1997-2004, 987: 2005-2012) and Cayman (987: 2006-2012), feature the Rear Sway Bar Bushing - 18.5 mm as an integral part of their rear suspension systems. Tailored for an 18.5 mm rear sway bar, this bushing—typically made of rubber or enhanced polyurethane—secures the bar to the chassis, minimizing body roll and sharpening handling precision during cornering. It absorbs vibrations and maintains stability, contributing to the balanced dynamics these Porsche models are known for. Over time, wear from driving stress or environmental factors can degrade the bushing, causing noise, looseness, or reduced responsiveness. Replacing it with a high-quality component is a straightforward upgrade for enthusiasts aiming to preserve the crisp, engaging performance of these iconic sports cars.
The Problem with OEM Bushings
Porsche OEM bushings use a rubber compound—typically 60-70 Shore A hardness—that degrades over time. Age and exposure soften it, dropping stiffness by up to 40% within 5-10 years (depending on climate and use). Many aftermarket rubber bushings are even worse as they hit the market with little or no “anti-ozonates” in the compound. This increases compliance, allowing unwanted suspension movement. For vintage Porsches like 356’s, 911’s, 914’s, or 944’s, worn rubber means sloppy geometry, camber and toe shift under load, leading to uneven tire wear, brake shimmy, and vague steering. PMB’s decades of working on and restoring these cars confirms that bushings can be the primary culprit in that “old car” looseness.
The PowerFlex Solution
PowerFlex bushings tackle this with a proprietary polyurethane compound, formulated at 80-85 Shore A hardness—25-30% stiffer than fresh OEM rubber. Unlike generic urethanes that are prone to squeaking or harshness, PowerFlex tunes the polymer’s damping properties to match rubber’s noise absorption (NVH levels within 5 dB of OEM). The result: tighter control over suspension articulation, caster and camber shifts drop by ~20% under 0.8g cornering loads without sacrificing ride quality.
Even new Porsches can gain from PowerFlex’s design. Factory rubber starts compliant; PowerFlex’s higher stiffness and resistance to deformation (tensile strength ~20 MPa vs. rubber’s ~10 MPa) sharpen response from day one. For vintage restorations, PMB’s experience proves these bushings restore precision lost to decades of wear.
Material & Design Specs
- Polyurethane: 80-85 Shore A, cured to a Tg above 200°F for heat stability.
- Stiffness Gain: 25-30% over new rubber, verified via static load testing.
- Fitment: Modeled from OEM Porsche bushings, tolerances ±0.1mm, no mods needed.
- Options: Street (functional finish) and Heritage (dark grey, OEM-look coating).
Why PowerFlex with PMB?
- Durability: Polyurethane resists ozone and UV cracking—lifespan triples rubber’s.
- Control: Reduces suspension play, cuts tire wear, stabilizes braking.
- Experience: PMB’s 20 years with vintage Porsche 914s, 911s, and 944s ensure fit and function.