Vehicle Covered in this Guide
2005-2012 Porsche Cayman, Cayman S, Cayman R, Boxster, Boxster S, Boxster Spyder. Fitment is identical between all models.
Chassis Introduction
With the introduction of the Cayman, the first fixed hardtop mid-engine car from Porsche was born. Porsche engineers created a proper track weapon with excellent structural rigidity, balance, and a potent powertrain to back it up. This chassis can support lower offset rear wheels due to its strut rear suspension, so their wheel specifications are unique amongst the other Porsche chassis.
| Bolt Pattern | Thread Pitch | Center Bore |
| 5x130mm | M14x1.5mm | 71.6mm |
OEM+ Fitment
- Front: 18x8.5” ET50 with 245/40-18 tires
Rear: 18x10” ET36 with 275/40-18 tires- Direct fit.
- Stock 235/40-18 and 265/40-18 tires can be used.
- 245/40-18 and 275/35-18 tires can also be used as a direct fit.
- 255/35-18 and 275/35-18 tires can also be used, but may require a touch of front negative camber depending on ride height and tire brand. With this tire setup, we strongly recommend using the 18x9" ET46 front wheel for superior sidewall support, see HPDE/Race fitment category below.
This fitment is a small step up from stock wheels and tires, but offers a noticeable improvement in the performance and aesthetic department. It is ideal for the driver who wants to upgrade to a no-nonsense direct bolt-on fitment, with no modifications required. By increasing wheel width by ½" up front and 1" on the rear compared to the stock base model configuration, these wheels offer superior sidewall support for either re-using stock tires or for enthusiasts who want to go with +1 tire sizing. Whether you are replacing the stock 18" wheels or downsizing from 19" wheels, this setup is not only wider, it will also decrease rotational mass.
Aggressive Street/HPDE Fitment
- Front: 18x8.5” ET42 with 245/40-18 tires
Rear: 18x10” ET36 with 275/40-18 tires
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A small amount of negative camber may be required up front depending on vehicle ride height, tire size and tire model.
- Stock 235/40-18 and 265/40-18 tires can be used.
- 245/40-18 and 275/35-18 tires can also be used as a direct fit.
- 255/35-18 and 275/35-18 tires can also be used, but may require a touch of front negative camber depending on ride height and tire brand. With this tire setup, we strongly recommend using the 18x9" ET46 front wheel for superior sidewall support, see HPDE/Race fitment category below.
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This staggered fitment is very similar to the one above, however the front wheels have a more aggressive offset which ultimately place them 8mm closer to the front fenders. This fitment is ideal for enthusiasts looking for a flush fitment with street tires, or for performance driving enthusiasts who have the ability to dial in negative camber with wider track compounds. This fitment also provides 8mm of additional brake caliper to spoke clearance.
HPDE/Race Fitment
- Front: 18x9” ET46 with 245/40-18 tires
Rear: 18x10” ET36 with 275/40-18 tires- Requires at least 2.0 degrees of front negative camber depending on ride height, tire size, and brand.
- 245/40-18 and 275/35-18 tires can also be used.
- 255/35-18 and 275/35-18 tires can also be used.
- 255/35-18 and 295/30-18 tires can also be used, but rear negative camber may be required.
- 245/645-18 and 305/660-18 slicks can also be used with additional front and rear 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 grip by maximizing contact patch. The 9” front wheel will provide superior sidewall support for wider tires, and may require aggressive negative camber specifications for proper front fender clearance depending on tire width and brand. This fitment is perfect for Spec Cayman racers who want to stay in compliance with class rules.
Big Brake Kit Clearances
The following brake setups have been tested and confirmed to clear:
- Brembo 1M1.9004A1, 380mm 6-pot - fits 18x8.5" ET42 & 18x9" ET46 only.
- Brembo 1B1.9016A1, 355mm 4-pot - fits all
- Brembo 1P1.8503A1, 365mm 4-pot - fits all
- AP Racing 13.01.0054, 355mm 4-pot - fits all
- StopTech 83.788.6700.51, 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