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718 Cayman/Boxster Wheel & Tire Fitment Guide

Bolt Pattern


Thread Pitch


Center Bore


Available Models




Vehicle Covered in this Guide
All 2017+ Porsche Cayman and Boxster chassis including the GT4 & Spyder.


* Please note, the 718 GT4 and Spyder require a minimum of a 19" wheel due to large brake specifications and rear suspension geometry that limits clearance. See the GT4/Spyder specific section at the bottom of the guide.

OEM+ Fitments


These 18" and 19" OEM+ fitments were developed specifically for the 718 Cayman/Boxster platform. They're best suited for drivers predominantly enjoying their car on the street, and/or for light track days and AutoX events. A combination of slightly wider wheel widths and perfected offsets provides enthusiasts with a more aggressive stance, and a meaningful increase in performance over the stock configuration without requiring a bunch of modifications to the car. Whether you want to re-use your stock tires or upgrade to "+1 tire sizing" (245 / 275), these easy to install wheel fitments have you covered. 


  • Front: 19x9" ET50 // Rear: 19x11" ET46


  • Typically a direct fit, but we encourage dialing in a small amount of negative camber up front to perfect the fitment. Negative camber will also improve handling through sharper turn-in and grip throughout the corners

HPDE / Club Racing Fitments


These fitments are best suited for weekend track warriors and competitive club racers looking to maximize grip and overall performance. 9” front wheels provide superior sidewall support over the more "generic" 8.5" front wheel option, which allows drivers to extract the most performance and longevity out of a given tire compound. Wider front wheel's and tires dramatically improve the cars ability to turn into the corners, and it mitigates unwanted understeer.


While the 9" wheels aren't very difficult to fit under the front fenders, there are many different tire sizes and compounds that can be used, many of which will require negative camber to prevent rubbing the front fenders under suspension compression. See high-level notes under each tire combination below, or contact one of our Porsche Product Experts by submitting a fitment request form to have a more detailed one-on-one conversation about your track/race car.

  • Front: 19x9" ET50 // Rear: 19x11" ET46

    • Popular Fitment


  • Alternative 1: Front: 265/35-19 // Rear: 295/35-19​

  • Alternative 2:  Front: 265/35-19 // Rear: 295/30-19​

  • Alternative 3: Front: 255/35-19 // Rear: 305/30-19​

  • Alternative 4: Front: 265/35-19 // Rear: 305/30-19​

Big Brake Kit Clearances
The following factory and aftermarket big brake setups have been tested and confirmed to clear:


GT4/Spyder Chassis

  • Factory Steel 6 piston 380mm - fits SM-10 19x9" ET50 only

  • Factory PCCB 6 piston 410mm - requires 20" wheels

  • AP Racing 13.01.10083  CP9661 6 piston 394mm - fits SM-10 19x9" ET50 only

All other Cayman/Boxster Chassis  

  • Factory Base 4 piston 350mm - fits all

  • Factory S/GTS 4 piston 350mm - fits all

  • Factory PCCB 6 piston 350mm - fits all

  • Brembo 1M1.9040A 6 piston 380mm - fits SM-10 18x8.5" ET42 & SM-10 18x9" ET46 only

  • Brembo 1N3.8021A 6 piston 350mm - fits all

  • AP Racing 13.01.10096 CP9661 6 piston 372mm - fits all

  • AP Racing 13.01.10072 CP9661 6 piston 355mm - fits all

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