Porsche 924 (1977) Wheel Fitment
Porsche 924 (1977): 4x108 bolt pattern, 57.1mm center bore. Factory wheels: F: 14x5.5J R: 14x5.5J. Reference fitment ranges.
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Wheel Size & Offset at a Glance
| Configuration | Wheel Size & Offset |
|---|---|
| Factory (OE) | F: 14x5.5J R: 14x5.5J |
| Flush Fitment | F 15x6.5J ET25 / R 15x6.5J ET25 |
| Maximum Aggressive | F 15x7J ET20 / R 15x7J ET20 |
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 924 runs a 4x108 bolt pattern, 57.1mm center bore, and a F: 14x5.5J wheel from the factory. Our Flush Fitment reference is F 15x6.5J ET25 / R 15x6.5J ET25, which tucks the tire under the fender lip on a stock-height Porsche 924. Our Maximum Aggressive reference is F 15x7J ET20 / R 15x7J ET20 — beyond that offset, expect rubbing against the inner fender liner under compression without further trimming.
Porsche 924 OE Wheel Specs
The 1977 Porsche 924 (Sports Coupe) uses a 4x108 bolt pattern with a 57.1mm center bore. Factory wheels are F: 14x5.5J R: 14x5.5J.
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 15x6.5J ET25 / R 15x6.5J ET25 is the recommended starting point on a stock or mildly lowered Porsche 924.
Maximum Aggressive Fitment
F 15x7J ET20 / R 15x7J ET20 is a more aggressive reference setup. Beyond this, expect rubbing under compression without fender rolling or camber correction.
Real-World Fitment Notes
The base 924's 4x108 pattern is inherited from its Audi/VW parts-bin hub and limits the pool of forged options compared with the Porsche-hub 5x130 cars; many owners eventually fit the M471 big-brake package specifically to gain access to the 5x130 catalogue covered on the 924 Turbo page.
5-Tier Configuration Options
A Factory-Style F 14x5.5J ET23 / R 14x5.5J ET23
Recommended setup: F 14x5.5J ET23 / R 14x5.5J ET23 | 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 15x6.5J ET24 / R 15x6.5J ET24
Recommended setup: F 15x6.5J ET24 / R 15x6.5J ET24 | 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 15x6.5J ET25 / R 15x6.5J ET25
Recommended setup: F 15x6.5J ET25 / R 15x6.5J ET25 | 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 15x7.0J ET23 / R 15x7.0J ET23
Recommended setup: F 15x7.0J ET23 / R 15x7.0J ET23 | 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 15x7.0J ET20 / R 15x7.0J ET20
Recommended setup: F 15x7.0J ET20 / R 15x7.0J ET20 | 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 14x5.5J ET23 / R 14x5.5J ET23 | F 15x6.5J ET24 / R 15x6.5J ET24 | F 15x6.5J ET25 / R 15x6.5J ET25 | F 15x7.0J ET23 / R 15x7.0J ET23 | F 15x7.0J ET20 / R 15x7.0J ET20 |
| 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 14x5.5J ET23 / R 14x5.5J ET23
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 15x6.5J ET25 / R 15x6.5J ET25
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 15x7.0J ET20 / R 15x7.0J ET20
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 14x5.5J ET23 → ~4.16″ F backspacing, R 14x5.5J ET23 → ~4.16″ R backspacing
- Flush: F 15x6.5J ET25 → ~4.73″ F backspacing, R 15x6.5J ET25 → ~4.73″ R backspacing
- Max: F 15x7J ET20 → ~4.79″ F backspacing, R 15x7J ET20 → ~4.79″ 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 924? Contact ANKUSI with your bolt pattern and offset target and we will confirm the correct forged wheel spec for your build.