Are you building your Porsche GT4 RS as a track car? Then safety should be the first thing on your list, ahead of power, tires or aero. A roll bar is a major part of that, but it works best as part of a complete system: a racing suit, gloves, shoes, a helmet and a head-and-neck restraint to go with your harnesses. At Competition Motorsport, we offer all of it, and we design and build the roll bar ourselves.
A purpose built GT4 RS roll bar is designed around the car’s own structure, interior and engine access instead of being adapted from a universal design. Our CMS Performance bar mounts to the rear bulkhead and rear shock towers, positions your harness shoulder straps correctly, and installs without cutting the carpet.
Why Can’t a Universal Roll Bar Do the Job?
The GT4 RS is a mid-engine, naturally aspirated 4.0-liter flat-six car (493 hp) built for the circuit first. Its carbon fiber intakes, engine cover and lightweight bucket seats show how much thought went into the layout, and that tight packaging makes the roll bar a harder design problem than it looks.
A universal bar assumes it can place tubes wherever the chassis allows, and the GT4 RS doesn’t allow much. The engine sits directly behind the driver, the carbon intakes and engine cover occupy the space a traditional rear brace would use, and the interior is trimmed to a high standard. A bar not designed for these constraints usually compromises on something: mounting location, rear visibility, engine access or interior condition. We designed ours so it doesn’t have to.
Where Does Our Bar Mount?
The main hoop mounts to the frame structure across the rear bulkhead. The rear kickers route over the carbon fiber intakes and engine cover and bolt to the GT4 RS rear shock towers. We chose these points because they are the strongest available, and they add rigidity to the chassis and suspension.
The kickers also keep the bar out of the engine bay. Because we don’t need rear diagonal bracing, your rear view stays clear and the engine cover opens without removing any part of the bar. That matters in a car that sees regular track time, where you check fluids and work on the car often.
Why Do We Build the Bar From Docol R8?
The main hoop and kickers use 1.75" x .095" Docol R8 Advanced High-Strength Steel tubing, joined with CNC-machined interlocking steel joints and CNC-cut carbon steel mounting plates. The harness cross-bar is 1.5" tubing. Everything is 360° TIG welded.
We use Docol R8 because it’s stronger and more ductile than the chromoly tubing commonly used in roll bars. Ductility matters because the structure has to absorb energy and deform rather than crack. For more on the metallurgy, see our Docol R8 explainer.
How Does the Bar Position Your Harness?
Short answer: The cross-bar puts your shoulder straps at 0° to -20° relative to the driver, about 8 inches behind the shoulders.
Shoulder-belt geometry affects how a harness loads you in a crash. A belt mounted too high or too low changes how force passes through the shoulders and spine. Harness manufacturers publish recommended angle ranges, and we designed the cross-bar to land inside that window. It also doubles as a mounting point for an HD racing video camera.
Does the Bar Require Cutting Anything?
No. It installs without cutting the center carpet, so you can return the car to stock later. Replacing cut carpet is expensive, and we wanted an installation you can fully reverse. If you want to retain your original trim, we also offer pre-cut OEM Porsche interior trim as an option.
Installation takes roughly 3 to 4 hours using our step-by-step instructions. The main hoop is one piece and the kickers come in three pieces, which keeps the parts manageable to fit.
Which Colors Can You Choose?
We powder coat every bar in-house at no additional charge. Choices include Arctic Grey, Gentian Blue, Gloss Black, GT Silver, Guards Red, Racing Yellow, Satin Black, Shark Blue, Superchrome, Weissach Blue and White, and you can call us for a custom color. We match colors to Porsche’s palette as closely as powder allows, and slight variance is normal.
Build the Full Restraint System
A roll bar is one part of your restraint system. We offer six-point harnesses (Schroth Enduro 2x2 GT4, Schroth Flexi 2x2 GT4, Sabelt Silver Series GT4) and four-point options (Schroth Profi II ASM GT4, Sabelt Porsche GT4) designed to bolt to the GT4 RS carbon bucket seats. If you run six-point harnesses, we strongly recommend adding our CMS Performance Sub Strap Mount for the anti-submarine strap.
CMS Performance GT4 RS Roll Bar at a Glance
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Fits: 2023+ Porsche 718 Cayman GT4 RS
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Part number: CPRB-GT4RS
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Material: 1.75" x .095" Docol R8 (main hoop and kickers), 1.5" harness cross-bar
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Construction: 360° TIG welded, CNC-machined interlocking joints
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Hardware: American-made Grade 8 included
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Install time: 3 to 4 hours
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Lead time: typically 2 to 3 weeks
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Price: $2,795
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Use: Off-road and race track use only
Frequently Asked Questions
Does the GT4 RS roll bar require cutting the carpet?
No. It installs without cutting the center carpet, so you can return the car to stock.
Can I still access the engine with the bar installed?
Yes. The engine cover opens without removing any part of the bar.
How long does installation take?
About 3 to 4 hours with our included instructions.Â
What harnesses work with this bar?
Six-point and four-point Schroth and Sabelt harnesses designed for the GT4 RS bucket seats. We recommend a sub strap mount with six-point harnesses.
Ready to Build Your GT4 RS for the Track?
Shop the CMS Performance Roll Bar for the Porsche 718 Cayman GT4 RS, or call us at 844-438-7244 and we’ll help you pair it with the right seat, harness, driver gear and head-and-neck restraint.
