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As you might have seen in our recent survey thread, APEX is working with the Porsche community in an effort to produce track wheels that offer unprecedented value. We have received 800+ survey responses from fellow community members offering feedback and fitment requests. The 987/981 chassis represented approximately 32% of the surveys submitted, so we’d love to hear more from this community. If you haven’t chimed in yet, you can still provide valuable feedback by taking our Porsche wheel survey here.
Before we can move forward, we need to fine tune certain fitment specifications for the 987/981 chassis. So, we’re seeking your expertise and need detailed feedback on the specs we believe should be produced.
Below is a list of all widths and offsets we’re looking to create for a variety of Porsche chassis in the first round of production. Fitments specific to the 987/981 chassis can be seen listed below. In accordance with the survey results, these will be produced in 18” sizes first and 19” thereafter. Survey data and community feedback will directly determine what will be produced, and when. Please note that both the SM-10 and EC-7 designs are being reviewed for feasibility. In your comment, please include tire sizes, tire model, and alignment settings if you have a change request so we can track developing trends.
Front:
F: 18x8.5” ET50 with 235/40-18, 245/40-18
F: 18x8.5” ET42 with 235/40-18, 245/40-18
F: 18x9” ET48 with 245/40-18, 255/35-18
Rear:
R: 18x10” ET36 with 265/35-18, 275/35-18
R: 18x10.5” ET40 with 285/30-18, 295/30-18
On-Car Rendering Gallery
I’d like to invite you to view new on-car imagery which help depict concavity profiles, finishes, and designs. The first round of images shown are the SM-10 design, however, the EC-7 design will follow.
If you would like to view all of our high-res versions, please click the embedded images.
Here we have a rendering showing the 18" SM-10 in our three finishes against a Racing Yellow Cayman GTS. The front wheels are profile 1 concavity - the least amount of concave. The rear wheels are profile 2 concavity - medium amount of concave.
I hope 2018 brings you health, happiness, prosperity... and APEX wheels this spring!
Here we have a beautiful basalt black 996 GT3 on 18" SM-10 in our three finishes. Similarly to the rest, these front wheels are concavity profile 1 (least concave). The rear wheels are concavity profile 2 (medium concave).
To answer the numerous people asking for concavity profile clarification, here’s a general overview of how they’re presented and produced for each specific application.
We offer our Porsche-specific APEX SM-10 and EC-7 in two or three different concavity profiles. Pending design and final engineering/strength optimization, the wheels will vary in concavity depth from profile one to three; one being the least concave, three being the most concave. Typically, the level of concavity is dependent on the width and offset of the wheel. The wider the wheel and lower the offset, the more concave. Whereas the skinnier the wheel and higher the offset, the less concave. While the amount of concavity may differ, some wide(r) and low(er) offset wheel specifications have a deeper “pocket” or center pad where the studs/lug nuts attach to the hub.
The varying concavity profiles in the SM-10 and EC-7 ensure that spoke curvature and brake clearance is never compromised due to width or offset changes in the wheel. The SM-10 and EC-7 are of the few 18" VIA/JWL certified wheels on the market that can clear both an aftermarket and OEM 380mm rotor 6-piston brake kit.
We are now making final tweaks in the engineering phase, prior to launching our initial pre-order/group buy next month. We’ll continue to update the community through the different phases of production, and will continue to release on-car photography to give enthusiasts a better idea of how some of these proposed wheel designs visually appear on specific chassis. Stay tuned for updates and solidified ETAs!
Please let me know if you have any further comments, questions, or fitment change requests.
Thanks to the community, we’ve nearly finalized our proposed 18” wheel specifications. As you may very well know, seemingly minute millimeter differences in wheel offset can result in large differences in overall wheel fitment. It directly determines how the wheel fits, performs, and is often times the deciding factor between it working, working well, or ultimately not working. With this said, we need your assistance in deciding between a handful of offsets for our 9” front option.
18x9” ET48: least inner (suspension) clearance, more outer (fender) clearance
18x9” ET47: 1mm more inner clearance, 1mm more aggressive towards the fender
18x9” ET46: 2mm more inner clearance, 2mm more aggressive towards the fender
18x9" ET45 or below -
For example, the +48 offset has approximately ~2mm of inner clearance (wheel to bottom spring perch) with linear spring equipped Ohlins coilovers. We’re unsure if this is the case across the board with all linear spring coilovers as it’s dependent on the use of a helper spring, spring length, inner diameter, etc, etc, so we’d like to hear your thoughts. Since it will not require a change in negative camber settings from the original +48, our suspicion is that the +46 is the best option to compensate for any tire deflection under severe load while on track. We typically like to see ~3mm of clearance to ensure ample clearance under any load, condition, or to account for tire deflection.
From a racers point of view, since we run alot of camber id prefer as much inner clearance as possible.
I haven't finished my suspension yet... But 0 scrub would be measured I'd be looking at
Assuming you're on the SPC JRZ suspension, you should have ample inner clearance with the ET46 without the use of spacers. Through community feedback from SPC racers and others alike, it seems like we've nixed the ET48 proposal and are replacing it in favor of an ET46 - ET44. I'll be emailing you shortly with some finalized information that you were hoping for last month. Talk soon, Jeff!
While a 997 GT3 equipped with cup flares can accommodate our profile 2 concavity wheel specifications in the front, we opted to show what front (profile 1) & rear (profile 3) wheels would typically be seen. Here is some on-car imagery of 18" APEX SM-10 on our longtime friend & partner, BRRacing's, 997.2 GT3.
We are making final advancements in the engineering and initial production stages prior to our initial pre-order/group buy. Please take this opportunity to share your fitment thoughts as enthusiast feedback is integral to product development.
Seen below is an IMSA ST 987 Boxster on 18” APEX SM-10. Equipped with a plethora of suspension components and Continental slicks, look out for this car on your East Coast racetracks and classified ads!
A Brembo GT brake kit is stuffed underneath the SM-10. Flaunting 380mm rotors and 6-piston front calipers, they clear the 18” SM-10 spokes and barrels with ease. Do not be forced into running larger diameter wheels than desired due to inferior brake clearance.
12-06-2017, 09:08 PM
APEX | Porsche Track Wheel Development
