987 Wheel & Tire Fitment Guide

Vehicle Covered in this Guide
2005-2012 Porsche Cayman, Cayman S, Cayman R, Boxster & Boxster S. 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: 5x130 Thread Pitch: M14x1.5mm Center Bore: 71.6mm


OEM+ Fitment

  • Front: 18x8.5” ET50 with 235/40-18 tires
    Rear: 18x10” ET36 with 265/35-18, 265/40-18 tires
    • Direct fit. 
    • 245/40-18 and 275/35-18 tires may also be used as a direct fit.

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 the front wheel width by ½” and the rear by 1” over the stock configuration, these wheels offer superior sidewall support for wider tires and greatly decrease rotational mass.


Aggressive Street/HPDE Fitment

  • Front: 18x8.5” ET42 with 245/40-18 tires
    Rear: 18x10” ET36 with 275/35-18, 275/40-18 tires
    • Requires at least 1.5 degrees of front negative camber.

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 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.


Performance Street/Track or Race Fitment

  • Front: 18x9” ET46 with 245/40-18 tires
    Rear: 18x10” ET36 with 275/35-18 tires
    • Requires at least 2 degrees of front negative camber.
    • 255/35-18 front tires may also be used but will require at least 2.5 degrees of front negative camber.
    • 265/35-18 and 285/35-18 tires may also be used but will require at least 3.0 degrees of front negative camber.
    • 295/30-18 rear tires may also be used but will likely require a fender roll and appropriate 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. It maximizes both front and rear tire widths, and is perfect for those SPC racers who want to stay bound to their sanctioned rulebook.  


Big Brake Kit ClearancesBrake-Clearance.jpgThe 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


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