Radium 20-0055 Rear Clamshell Shim Kit Aluminum for Lotus Exige All

Vehicle Fitment

• Lotus Exige - All Model Years, All Trims (Rear Clamshell Body Shim Replacement)

Fitment Notes

• Designed as a direct replacement for the factory steel rear clamshell body shim spacers located at the 4 trunk-mounted through-hole attachment points on the rear subframe.
• Shim thickness is consistent with the factory shim stack. Minor variance from the exact OEM stack height is possible but no noticeable difference in rear clamshell body fitment or alignment will result.
• Initial installation (including factory shim removal and clamshell refit) typically takes 1.5-2 hours. With the optional modifications detailed in the included instruction manual, subsequent clamshell removal time can be reduced to 10 minutes or less.
• Comprehensive installation instructions are included and cover: factory shim removal, Radium shim installation, and additional guidance on further improving rear clamshell removability.
• Sold as a complete kit - all required hardware included. No additional hardware needed for installation.

Features

• Permanently secured design eliminates the core failure mode of the factory shims - the factory steel shims are taped to the rear subframe and lose adhesion over time, causing misalignment with the 4 clamshell through-holes and allowing shims to slip out of position or get lost during clamshell removal.
• Radium shims bolt permanently in place using stainless steel countersink M6 screws and conical M6 oval locking pinch nuts, maintaining consistent alignment with the clamshell through-holes every time the body panel is removed and reinstalled.
• Laser cut from 5052 aluminum plate with lightweight cutout features for maximum weight reduction without sacrificing structural integrity.
• Media blasted and black anodized finish protects against oxidation and corrosion in the rear subframe environment.
• 73% lighter than the factory steel shim stack - a meaningful reduction given the location directly on the chassis.
• Manufactured in the USA by Radium Engineering; detailed installation instructions included.

Specifications

• Part Number: 20-0055
• Application: Lotus Exige - All Model Years, All Trims
• Position: Rear Clamshell Body Shim - Rear Subframe (4 attachment points)
• Shim Material: 5052 Aluminum Plate (laser cut)
• Finish: Media Blasted, Black Anodized
• Hardware: Stainless Steel M6 Countersink Screws and Conical M6 Oval Locking Pinch Nuts
• Weight Savings: 73% vs. factory steel shim stack
• Quantity: Complete Kit (4 shims + 4 screws + 4 nuts + instructions)
• Manufactured: USA

Included Components

• 4x Laser Cut Anodized Aluminum Body Shims
• 4x Stainless Steel Countersink M6 Screws
• 4x Conical Top M6 Oval Locking Pinch Nuts
• 1x Detailed Installation Instructions (includes clamshell removal procedure and tips for reducing future removal time)

Product Description

The Radium Engineering 20-0055 is a lightweight aluminum replacement shim kit for the rear clamshell body attachment points on all Lotus Exige models. The factory Lotus setup uses steel shims taped to the rear subframe at the 4 trunk-mounted through-holes - a system that becomes increasingly problematic on cars where the rear clamshell is removed frequently for engine access, track prep, or maintenance. Over time, the tape loses adhesion, causing the shims to lose alignment with the through-holes, slip out of position relative to each other, or fall out entirely and get lost. The Radium kit solves this permanently by replacing the taped steel shims with laser-cut 5052 aluminum shims that bolt directly to the subframe using stainless steel M6 countersink screws and conical locking pinch nuts, keeping them precisely located at all times regardless of how often the clamshell is removed.

The aluminum shims are media blasted and black anodized for corrosion resistance, and their laser-cut lightweight features bring the total shim stack weight down by 73% compared to the factory steel pieces - a straightforward weight reduction at a chassis location that benefits from it. Shim thickness is consistent with the OEM stack; minor variance is inherent to the design but produces no perceptible difference in clamshell fitment or alignment. Initial installation takes approximately 1.5-2 hours and includes removal of the rear clamshell and factory shims; the included instruction manual covers the full procedure in detail and includes additional guidance on further modifications that can reduce subsequent clamshell removal time to 10 minutes or less. All hardware included; manufactured in the USA.