Vehicle Covered in this Guide
2017+ Porsche Cayman, Cayman S, Cayman T, Cayman GTS, Boxster, Boxster S. Fitment is identical between all models - GT4 and Spyder excluded.
| Bolt Pattern | Thread Pitch | Center Bore |
| 5x130mm | M14x1.5mm | 71.6mm |
OEM+ Fitment
- Front: 18x8.5” ET42 with 235/45-18 tires
Rear: 18x10” ET36 with 265/45-18 tires- Front negative camber of -1.5º or more recommended.
- 245/40-18 and 275/40-18 tires may also be used.
This fitment is a small step up from stock wheels and tires, but offers a noticeable improvement in the performance and aesthetic department. Wider, lighter, and a smaller diameter than the OEM specifications, this fitment is flush with the wheel arches and decreases rotational mass. Moving to 18" wheels also provides more track-oriented tire compounds and significantly mitigates seasonal tire budget.
Performance Street/Track or Race Fitment
- Front: 18x9” ET46 with 245/40-18 tires
Rear: 18x10” ET36 with 275/40-18 tires- Requires at least 2 degrees of front negative camber.
- 255/40-18 and 275/40-18 tires may also be used but will require at least 2.5 degrees of front negative camber.
These fitments are effective for both weekend and dedicated track warriors. This no-compromise fitment is ideal for track use where enthusiasts want to maximize front end grip by minimizing the stagger between front and rear. The 9” front wheel will provide superior sidewall support for wider tires, and it relies on aggressive negative camber specifications for proper front fender clearance. Dialing in front negative camber is necessary since you'll be using all available real estate under the fender arches to accommodate this wider wheel and tire configuration.
Big Brake Kit Clearances
The following brake setups have been tested and confirmed to clear:
- Brembo 380mm 6-pot - fits all
- AP Racing 355mm 4-pot - fits all
- StopTech 355mm 6-pot - fits all
Please email or call us with any other questions related to brake clearance and we’ll be happy to help.
Still have questions?
Fill out our Fitment Recommendation form
Call us: 925-245-0773
Email us: support@apexraceparts.com