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1977 Porsche 924 Wheels & Rims: Bolt Pattern, Offset & Sizes
Fitting Porsche 924 wheels? This page gives the 1977 Porsche 924 bolt pattern (4x108), centre bore, factory rim size and the offset range for aftermarket and forged Porsche 924 rims: the same spec sheet ANKUSI uses when machining forged wheels for this car.
Quick answer: The 1977 Porsche 924 uses a 4x108 bolt pattern with a 57.1 mm centre bore and M12x1.5 lug nuts. Factory wheels: F: 14x5.5J R: 14x5.5J. For aftermarket wheels, 15x6.5J ET25 sits flush and 15x7J ET20 is the most aggressive fit.
Forged wheels for the 1977 Porsche 924 — drilled 4x108 with a 57.1 mm centre bore, built to the offset you choose. From $220 per wheel, made to order in 20–25 days.
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Porsche 924 (1977): 4x108 bolt pattern, 57.1mm center bore. Factory wheels: F: 14x5.5J R: 14x5.5J. Reference fitment ranges.
Bolt Pattern4x108
Wheel Bolt/NutM12x1.5 Nut
Center Bore57.1mm
Wheel Load Rating550–650 kg/wheel (Classic Sports Car segment reference)
Caliper TypeSolid front disc brakes, Audi/VW-sourced hub (OEM, Porsche 924 base)
Year1977
CategorySports Coupe
✓ Data check: the bolt pattern and center bore on this page match an independent fitment reference. Last reviewed September 18, 2026. How we verify
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 |
Forged Wheel Designs for the Porsche 924
Every design below is forged to order, so it can be machined to the Porsche 924's 4x108 bolt pattern and 57.1 mm center bore, with the width and offset calculated for your setup.
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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
ANKUSI builds these wheels — we are the forging factory, not a reseller. For the Porsche 924 (1977) we drill the 4x108 pattern and cut the centre bore to 57.1mm on our own CNC line, so the wheel hub-centres on the car with no spacer rings, in whatever diameter, width and offset you specify.
Converting these ET figures to backspacing? Use the wheel offset and backspacing calculator.
The figures on this page are part of our open wheel fitment dataset — 10,093 vehicles, free to download, CC BY 4.0.
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.
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.
Vehicles With the Same Hub as the Porsche 924 (4x108, 57.1 mm Bore)
In our database, 6 other Audi entries use exactly the same 4x108 bolt pattern and 57.1 mm center bore. Factory wheels from these cars bolt on and center on the hub without rings; offset and width still have to be checked.
4x108 is used by 2.6% of the vehicle pages in our English fitment guide (171 of 6,503); 4.1% of those also use a 57.1 mm center bore.
Hub-Centric Rings for a 57.1 mm Center Bore
A wheel with a center bore larger than 57.1 mm needs a hub-centric ring. The most common combinations:
| Wheel bore | Ring size |
|---|---|
| 60.1 mm | 60.1 → 57.1 mm |
| 63.4 mm | 63.4 → 57.1 mm |
| 64.1 mm | 64.1 → 57.1 mm |
| 65.1 mm | 65.1 → 57.1 mm |
| 73.1 mm | 73.1 → 57.1 mm |
ANKUSI forged wheels are bored to exactly 57.1 mm for this vehicle, so no ring is needed.
Frequently Asked Questions
What bolt pattern (PCD) does the Porsche 924 use?
The 1977 Porsche 924 uses a 4x108 bolt pattern.
How many lug bolts does the Porsche 924 use?
The Porsche 924 uses a 4-lug bolt pattern (4x108), so you need a 4-lug forged wheel to bolt straight on.
What is the center bore size on the Porsche 924?
The Porsche 924's center bore is 57.1mm. If an aftermarket wheel has a larger center bore than this, hub-centric rings are recommended so the wheel centers on the hub itself rather than relying on the lug bolts alone.
What size are the factory (stock) wheels on the Porsche 924?
Factory wheels on the Porsche 924 are F: 14x5.5J R: 14x5.5J.
What is the biggest wheel size I can fit on my Porsche 924 without rubbing?
The most aggressive fitment we recommend without fender work is F 15x7J ET20 / R 15x7J ET20. Going beyond this typically causes rubbing under compression unless you roll the fenders or add camber correction.
What does a flush wheel fitment look like on the Porsche 924?
For a flush look with minimal to no rubbing, we recommend F 15x6.5J ET25 / R 15x6.5J ET25 as a starting point on a stock or mildly lowered Porsche 924.
Do I need wheel spacers for my Porsche 924?
No. ANKUSI forges each wheel to your exact target offset, including the flush or max specs above, so you get the correct fitment without stacking spacers. Spacers are typically only used to push out an existing OE-offset wheel without replacing it, which isn't necessary when you're ordering a custom-offset forged wheel.
How do I calculate wheel backspacing for my Porsche 924?
Backspacing (in inches) = wheel width (in) ÷ 2 + offset (mm) ÷ 25.4 + 0.5 (flange allowance). For example, the flush spec above works out to roughly 4.73" backspacing up front and 4.73" in the rear.
What's the difference between wheel offset and backspacing?
Offset is the distance in millimeters from the wheel's true centerline to its mounting face (positive offset pulls the wheel in, negative pushes it out). Backspacing is the distance in inches from the mounting face to the back edge of the wheel barrel. They describe the same fitment from two different reference points, which is why ANKUSI lists both above — some shops and tuning guides quote offset, others quote backspacing.
Can I run staggered wheels (different sizes front and rear) on my Porsche 924?
Yes — the Porsche 924's factory and our recommended flush/max fitments already use staggered sizing (different width front and rear), and ANKUSI can forge matching staggered sets to your target offsets.
Sources and Last Update
Data checked against: avtoreference.com.
This record is part of the open ANKUSI Wheel Fitment Dataset (DOI 10.5281/zenodo.23241521, CC BY 4.0).
Other cars on the same factory size: 14x5.5 wheels · 14 inch wheels.
Compiled by the ANKUSI Wheels engineering team, an IATF 16949 and ISO 9001 certified forged wheel factory in Guangzhou.