Case Study: Annex Suspension Group — BRZ/FRS/GR86 Coilover Top Hat Bushings
The problem:
Annex Suspension Group wanted to reduce NVH on their GR86/BRZ coilovers by replacing harsh spherical bearings with a stacked 90A polyurethane bushing setup. However, the cast bushings were plastically deforming in the field. The combined forces of static nitrogen preload (~30 lbs), dynamic damping loads, and violent bump-stop impacts were pushing the standard cast urethane past its elastic limit, causing permanent compression set.
The Manufacturing Bottleneck
Annex was casting from needed a tougher material—like Covestro's TEXIN 392a, a highly creep-resistant, ester-based TPU. However, high-grade TPUs are incredibly difficult to source for small-batch casting, and machining new molds for every geometric iteration was financially unviable.
Perry Parts bypassed traditional tooling entirely. Using our direct-print TPU process, we manufactured prototype bushings out of industrial-grade TEXIN 392a, matched exactly to the existing top hat hardware. No molds, no minimum order quantities, and zero compromises on material science.
The Results
24-Hour Static Load Testing To validate the material, we ran a two-phase compression test comparing the original cast bushings directly against the 3D printed TEXIN 392a parts.
Phase 1 (500 lbs / 24 Hours): The 3D printed parts vastly outperformed the cast urethane, exhibiting 66% less compression set on the critical load-bearing lower bushing.
Cast Urethane 0.56mm
Perry Parts 0.19mm
Phase 2 (2,200 lbs / 24 Hours): Escalating the test to simulate worst-case track impacts, the cast urethane exhibited severe lateral "pillowing." The 3D printed parts maintained their structural geometry significantly better under extreme loads.
The Outcome After reviewing the Phase 2 data, Annex moved directly to production. 100 bushings were printing within 24 hours of payment and shipped in three days. As an added value, Perry Parts engineered a complementary bump stop redesign that routes high-magnitude impact loads directly into the top hat structure, bypassing the bushing stack entirely to guarantee long-term reliability.
Takeaway
Perry Parts offers engineering consulting, rapid prototyping, and scalable production for elastomeric components. If you can mold it, we can print it—faster, cheaper, and higher performing.
We have worked with
