2025 Porsche Kellymoss GT4R Lowered with Rotiform COS Forged Wheels

Porsche Kellymoss GT4R Wheel and Tire Setup

This Porsche Kellymoss GT4R takes an already serious track-focused platform and pairs it with custom Rotiform COS forged wheels and Yokohama ADVAN tires. The combination keeps the visual focus on performance, with an open wheel design that exposes the large braking system and complements the aggressive aerodynamic bodywork.

The Rotiform COS is a custom forged wheel design that can be produced specifically around the vehicle’s required width, offset and brake clearance. On a build this specialized, those measurements are especially important, which is why the exact front and rear wheel specifications should be verified before using them as fitment guidance.

Kellymoss GT4R Performance Platform

The Kellymoss GT4R is based on the Porsche GT4 RS Clubsport platform and has been extensively reengineered for additional grip, reduced weight and improved track performance. Kellymoss developed the GT4R with wider bodywork, revised aerodynamics and significant suspension changes rather than treating it as a cosmetic upgrade.

That wider body allows the GT4R to accommodate substantially wider wheel and tire packages than a standard GT4 RS Clubsport. The finished car has a much broader track and an aggressive stance designed around performance rather than appearance alone.

Rotiform COS Forged Wheels

The Rotiform COS is available as a custom forged wheel and can be configured around specific diameters, widths, offsets and brake packages. Forged construction makes it particularly appropriate for a performance-focused Porsche where wheel strength and rotating mass both matter.

The COS design also leaves much of the brake package visible through the wheel face, fitting the motorsport character of the GT4R while maintaining a clean and purposeful appearance.

Fitment and Stance

This GT4R sits on a lowered, track-oriented suspension setup that brings the body tightly around the wheel and tire package. The combination creates very little unnecessary wheel gap and emphasizes the wider proportions of the Kellymoss bodywork.

Because the exact front and rear wheel widths, offsets and Yokohama tire sizes for this particular vehicle have not yet been confirmed, rubbing, inner clearance, tire diameter and fender position should not be estimated. Those specifications should be documented from the actual build before being presented as verified fitment data.

Ride and Performance

This is a performance-driven setup rather than a conventional street stance build. The forged wheels help control unnecessary rotating mass while the Yokohama ADVAN tires are chosen around grip and response.

Kellymoss also substantially revises the GT4R suspension and chassis compared with the underlying Porsche platform, so wheel fitment on this car should be treated as specific to the GT4R rather than assumed to transfer directly to a standard Cayman GT4 RS or GT4 RS Clubsport.

Fitment Dynamics Miami

Fitment Dynamics works with custom forged wheel and tire packages for Porsche performance applications, including track-focused and specialty builds. Our team can help verify wheel diameter, width, offset, brake clearance and tire sizing before producing or installing a custom setup.

Customers can visit Fitment Dynamics in the Miami area for professional wheel and tire installation, fitment assistance and local pickup, or have custom wheel and tire packages shipped nationwide directly to their door.

Fitment Dynamics
8224 NW South River Dr
Medley, FL 33166
786-244-5565