Porsche 928 GTS (1993) Wheel Fitment
Porsche 928 GTS (1993): 5x130 bolt pattern, 71.6mm center bore. Factory wheels: F: 17x8J R: 17x9J. Reference fitment ranges.
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Wheel Size & Offset at a Glance
| Configuration | Wheel Size & Offset |
|---|---|
| Factory (OE) | F: 17x8J R: 17x9J |
| Flush Fitment | F 17x9J ET50 / R 17x10J ET40 |
| Maximum Aggressive | F 18x9J ET45 / R 18x10.5J ET40 |
How to Read Wheel Offset & Measurements
Use these two references before ordering: the left diagram shows where each spec (PCD, center bore, offset, width and diameter) is measured on the wheel; the right diagram shows how positive, zero and negative offset shift the wheel face relative to the hub centerline.
ANKUSI Engineering Expert Advice
Coupes and performance platforms are where rotational mass shows up fastest — in acceleration, in braking, and in how quickly the chassis changes direction. Forging lets us build to the same strength spec as the factory wheel at a meaningfully lower rotational weight, which is where the performance gain actually comes from, not just the visual one.
The Porsche 928 GTS runs a 5x130 bolt pattern, 71.6mm center bore, and a F: 17x8J wheel from the factory. Our Flush Fitment reference is F 17x9J ET50 / R 17x10J ET40, which tucks the tire under the fender lip on a stock-height Porsche 928 GTS. Our Maximum Aggressive reference is F 18x9J ET45 / R 18x10.5J ET40 — beyond that offset, expect rubbing against the inner fender liner under compression without further trimming.
Porsche 928 GTS OE Wheel Specs
The 1993 Porsche 928 GTS (Sports Coupe) uses a 5x130 bolt pattern with a 71.6mm center bore. Factory wheels are F: 17x8J R: 17x9J.
Why the factory spec works for most owners:
- Keeps unsprung weight low to preserve the factory handling balance
- Matches the wider, performance-oriented tire sizing typical of this platform
- Maintains clearance for the factory brake package and suspension geometry
- Balances grip with ride comfort for daily and spirited driving
Flush Fitment
For a flush look with minimal rubbing, F 17x9J ET50 / R 17x10J ET40 is the recommended starting point on a stock or mildly lowered Porsche 928 GTS.
Maximum Aggressive Fitment
F 18x9J ET45 / R 18x10.5J ET40 is a more aggressive reference setup. Beyond this, expect rubbing under compression without fender rolling or camber correction.
Real-World Fitment Notes
The GTS was the only 928 variant to leave the factory on staggered 17-inch 'Cup 2' design wheels; its wider rear track and factory-flared quarter panels give it noticeably more forged wheel headroom than the 16-inch early 928s, particularly at the rear.
5-Tier Configuration Options
A Factory-Style F 17x8.0J ET55 / R 17x9.0J ET40
Recommended setup: F 17x8.0J ET55 / R 17x9.0J ET40 | Economy impact: Negligible | Best for: Daily commuting, family use
Appearance: 7/10 | Comfort: 9.5/10 | Install difficulty: ★☆☆☆☆
Estimated cost: $450-800 (wheels + tires + install)
B Comfortable Upgrade F 17x9.0J ET53 / R 17x10.0J ET40
Recommended setup: F 17x9.0J ET53 / R 17x10.0J ET40 | Economy impact: -2 to -4% | Best for: Daily / street
Appearance: 8/10 | Comfort: 9/10 | Install difficulty: ★☆☆☆☆
Estimated cost: $1,950-2,550 (wheels + tires + install)
C Balanced / Flush Fit F 17x9.0J ET50 / R 17x10.0J ET40
Recommended setup: F 17x9.0J ET50 / R 17x10.0J ET40 | Economy impact: -4 to -6% | Best for: Street
Appearance: 8.5/10 | Comfort: 8/10 | Install difficulty: ★★☆☆☆
Estimated cost: $2,600-3,400 (wheels + tires + install)
D Aggressive F 18x9.0J ET48 / R 18x10.5J ET40
Recommended setup: F 18x9.0J ET48 / R 18x10.5J ET40 | Economy impact: -6 to -9% | Best for: Show / occasional track
Appearance: 9/10 | Comfort: 6.5/10 | Install difficulty: ★★★☆☆
Estimated cost: $3,900-5,000 (wheels + tires + install)
E Max Aggressive F 18x9.0J ET45 / R 18x10.5J ET40
Recommended setup: F 18x9.0J ET45 / R 18x10.5J ET40 | Economy impact: -8 to -12% | Best for: Show only
Appearance: 9.5/10 | Comfort: 4/10 | Install difficulty: ★★★★☆
Estimated cost: $4,800-6,200+ (wheels + tires + install)
Performance Comparison Matrix
| Metric | Tier A | Tier B | Tier C | Tier D | Tier E |
|---|---|---|---|---|---|
| Wheel Spec | F 17x8.0J ET55 / R 17x9.0J ET40 | F 17x9.0J ET53 / R 17x10.0J ET40 | F 17x9.0J ET50 / R 17x10.0J ET40 | F 18x9.0J ET48 / R 18x10.5J ET40 | F 18x9.0J ET45 / R 18x10.5J ET40 |
| Economy Impact | Negligible | -2 to -4% | -4 to -6% | -6 to -9% | -8 to -12% |
| Appearance | 7/10 | 8/10 | 8.5/10 | 9/10 | 9.5/10 |
| Comfort | 9.5/10 | 9/10 | 8/10 | 6.5/10 | 4/10 |
| Install Difficulty | ★☆☆☆☆ | ★☆☆☆☆ | ★★☆☆☆ | ★★★☆☆ | ★★★★☆ |
| Cost Range | $450-800 | $1,950-2,550 | $2,600-3,400 | $3,900-5,000 | $4,800-6,200+ |
| Best For | Daily commuting, family use | Daily / street | Street | Show / occasional track | Show only |
Real-World Reference Cases
The examples below are compiled from typical ANKUSI customer configurations and are labeled as reference cases, not individually verified real-world builds.
Case 1: Daily Driver (Factory-Style)
Profile: Everyday driving, prioritizes comfort and low running cost.
Setup: F 17x8.0J ET55 / R 17x9.0J ET40
Cost: ~$620
Outcome: Minimal visual change, ride and fuel economy essentially unaffected.
Case 2: Balanced Enthusiast (Balanced / Flush Fit)
Profile: Wants a sportier stance without sacrificing daily usability.
Setup: F 17x9.0J ET50 / R 17x10.0J ET40
Cost: ~$3,000
Outcome: Noticeable visual upgrade, fuel economy drop within the expected range.
Case 3: Show Build (Max Aggressive)
Profile: Built primarily for shows or occasional track/show use.
Setup: F 18x9.0J ET45 / R 18x10.5J ET40
Cost: ~$5,500
Outcome: Maximum visual impact; daily comfort and fuel economy are heavily compromised, physical test fit required before production.
Decision Guide
Offset & Backspacing Reference
Backspacing is calculated as wheel width (in) ÷ 2 + offset (mm) ÷ 25.4 + 0.5 (flange allowance):
- OE: F 17x8J ET55 → ~6.67″ F backspacing, R 17x9J ET40 → ~6.57″ R backspacing
- Flush: F 17x9J ET50 → ~6.97″ F backspacing, R 17x10J ET40 → ~7.07″ R backspacing
- Max: F 18x9J ET45 → ~6.77″ F backspacing, R 18x10.5J ET40 → ~7.32″ R backspacing
A Note on Clearance
Final clearance depends on the exact tire model, suspension height, brake package, alignment and vehicle tolerances. A physical test fit is recommended before production.
Want to check a different width or offset before you order? Use our Offset & Backspacing Calculator to solve the numbers yourself, or looking for your exact Porsche spec, or want a wheel built to a custom offset for your Porsche 928 GTS? Contact ANKUSI with your bolt pattern and offset target and we will confirm the correct forged wheel spec for your build.