Hardcore Track Fitment for Porsche Cayman GT4

It’s no secret that Porsche’s Cayman GT4 is an incredibly balanced, potent, and capable sportscar. Even in their stock form, these cars can be a formidable track weapon. However, there are fitment options and track-focused setups that can really accentuate the GT4’s remarkable performance in a way that’s ideal for cars that will be driven exclusively on-track. In this article, we’re going to walk you through our favorite hardcore track setups for the Porsche GT4.

One major piece of the GT4 track setup puzzle is downsizing from the stock 20” wheel to a 19”. Running 19” wheels with a 265 front tire and 305 rear tire is a very appealing combo; not only will the wider tires provide more grip, it opens up a wider selection of popular track tires that are only available in the 265/305 combo. That said, this fitment is quite aggressive and requires some fine-tuning to make work.

In order to make the 265 tire work, you’re going to need to add camber plates up front. Fitting camber plates at the innermost position on the factory slotted mounting holes will provide you with maximum clearance between the tire and fender, making room for the wider tire. Shimming the lower control arm is not an alternative to camber plates when it comes to running a 265 as it does not provide added clearance at the top of the tire near the fender. After installing the camber plates, you can then shim the lower control arm (LCA) to dial-in your desired camber value. It’s worth noting that when shimming the LCA, your caster value will be affected and may go out-of-spec, which will cause the wheel to no longer be centered within the wheel well. This can cause your tires to rub the front of the inner fender liner near the radiator outlet. If you dial-in enough negative camber for this to be an issue, you can remedy it by adding caster pucks to the LCA or using an adjustable caster arm (thrust arm).

Our 19x9” ET50 front wheel will run the 265/35-19, as well as narrower alternatives like a 245/40-19 or a 255/35-19. This is a good option if you do not want to install camber plates immediately and want to modify the car in stages, or if you want to run a 245 or 255 while you develop your skills as a driver. If running a 265/35-19 is your plan from the outset, then the wider 19x9.5” ET48 VS-5RS is the better choice for performance with the wider tire size.

The rear wheel we recommend for this setup is a 19x11” ET48, which requires Tarett Motorsport-style rear toe links regardless of which rear tire size you plan to use. This part is necessary to provide added clearance when stepping down from the OEM 20x11” ET50 to a 19x11” ET48 as the diameter reduction causes the inner lip of the 11” wheel to interfere with OEM and OEM-style toe links. For a 305/30-19 or a Hoosier 295/30-19, we suggest installing rear camber plates on the car. As with the front axle, being able to dial-in negative camber at the top mount is necessary for extra fender clearance with these wider tires, and it will reduce the amount of lower control arms shims needed to achieve a desired camber value. This all aids tire clearance and allows you to greatly increase the rubber you run on your GT4 and your grip. No guarantees on your lap times, though. That’s all on you.

Brandon is a Porsche Fitment Expert at APEX Wheels. Prior to joining APEX in 2022, he worked as Office Manager for a Porsche & Ferrari service and race shop, guiding customers in all areas – suspension, power, aesthetics, you-name-it. His first foray into racing came In college when he was asked to assist at a PCA club race. Says Brandon, “I figured if I am already making the drive, I might as well enter the HPDE happening at the same time.” He hasn't stopped since. Among the various cars he has owned and/or tracked are a ‘74 Corvette Convertible, ’74 Firebird Formula 400, ‘17 GTI, ‘07 Cayman S, and his current ride, a ‘12 Cayman R (BGB X51 pack 3.8L) with staggered APEX EC-7RS 18x9”ET46 & 18x10” ET36 in Motorsport Gold. Fun Fact: Brandon is a big fan of SIM racing, which he uses to learn about a new track he’s going to or get a refresher on a familiar track, as well as improve his racecraft.Have questions about wheels for your Porsche? Use our contact form and ask for Brandon.