📐 What Is Center Bore on Wheels (And Why Most People Ignore It)
You may have heard the term “center bore” or seen specs like 73.1mm or 66.6mm — but what do they actually mean? In this article, we’ll explain what the center bore is, why it matters when buying wheels, and how ignoring it can cause vibration, poor fitment, or even damage to your vehicle.
⸻
🔩 What Is the Center Bore (CB)?
The center bore is the large hole in the middle of the back of your wheel. It fits snugly over the raised circular lip (called the hub) on your car’s wheel hub.
✅ Its job? To center the wheel perfectly on the vehicle.
Without it, the wheel may sit off-center, causing serious problems.
⸻
🧠 Why Center Bore Is So Important
1. Prevents Vibration
If the center bore doesn’t match your car’s hub size, even a tiny gap (1-2mm) can cause:
• Steering wheel vibration
• Wobbling at highway speeds
• Uneven tire wear
2. Correct Fitment
A wheel that doesn’t fit perfectly on the hub may:
• Be hard to mount
• Put all the load on the bolts (which is unsafe)
• Cause balancing issues
3. Load Support
The center bore and hub carry the vertical weight of the vehicle. The bolts just hold it in place. Misalignment here = stress on studs.
⸻
🎯 OEM vs Aftermarket Center Bores
• OEM wheels are always hub-centric — meaning the center bore perfectly matches the car’s hub.
• Aftermarket wheels often have larger center bores (e.g., 73.1mm) to fit multiple cars.
This is where hub rings come in.
⸻
🧩 Hub-Centric Rings: The Fix You Didn’t Know You Needed
If your wheel’s CB is bigger than your hub:
• Use hub-centric rings to close the gap.
• Example: Wheel CB = 73.1mm, Car Hub = 66.6mm → Use a 73.1 to 66.6 ring.
These rings are usually made of:
• Plastic (cheaper, good for daily driving)
• Aluminum (durable, better for heat + off-road use)
⸻
🚨 Common Mistake: Ignoring Center Bore Size
Many people focus on:
• Bolt pattern (e.g. 5×114.3)
• Offset (ET)
• Wheel size (18”, 20”)
But forget to check what is center bore on wheels, especially with secondhand or universal fit wheels.
That’s when the problems start.
⸻
🧪 Real-World Example
A client installed aftermarket 19” wheels with 73.1mm center bore on a BMW 5 Series (which has a 66.6mm hub). No rings used.
Result:
• Slight vibration above 100 km/h
• Car pulled to the left
• Took it back twice for balancing — but issue remained
Solution?
Added 66.6mm hub-centric rings → vibration gone instantly.
⸻
🔗 • Shop Hub Rings (Plastic & Aluminum): https://wheelsae.com/
• Wheel Fitment Explained: PCD, Offset, CB: https://www.instagram.com/wheels_tire.ae/
⸻
🛠 Do All Cars Use the Same Center Bore?
Absolutely not. Even within the same brand, different models may use:
• Different hub sizes
• Different center bore specs
• Different bolt types
That’s why it’s critical to learn what is center bore on wheels for your exact vehicle before you shop.
⸻
⚠️ What Happens If You Ignore the Center Bore?
Let’s say you install aftermarket wheels with a 73.1mm center bore on a car with a 67.1mm hub, but don’t use rings.
Here’s what you may experience:
• Vibration starting at 80–120 km/h
• Inconsistent wheel balance
• Extra wear on wheel bolts
• Damage to studs over time
• Even cracking at the wheel seat after months
Knowing what is center bore on wheels helps you avoid all of this with a simple ring that costs under AED 50.
⸻
✅ Summary: Why CB Is One of the Most Ignored — But Most Important — Specs
When people ask about wheel specs, they usually focus on:
• PCD
• Width
• Offset
But now that you understand what is center bore on wheels, you know how much this tiny detail can affect the entire ride quality and safety of your vehicle.
⸻
