Wheel Diameter
Wheel diameter is measured in inches across the bead seat — not the outer edge. A 17-inch wheel requires 17-inch tires. Common diameters range from 14 inches for compact cars to 22 inches for luxury SUVs and trucks.
Larger diameters fill the wheel well for a more aggressive look but require lower-profile tires, which can make the ride harsher. Smaller diameters with taller tires provide more cushioning and are better for off-road use.
Wheel Width
Width is measured in inches across the bead seat. A 17x8 wheel is 17 inches in diameter and 8 inches wide. Wider wheels support wider tires, improving grip and stability. However, wheels that are too wide for the tire can cause poor bead seating and uneven wear.
As a general rule, tire width should be 20-40mm wider than wheel width. For an 8-inch wheel (203mm), a 225-245mm tire is appropriate.
Bolt Pattern (PCD)
The bolt pattern, or Pitch Circle Diameter (PCD), is written as NxY where N is the number of lug holes and Y is the diameter of the circle they form in millimeters. For example, 5x114.3 means 5 lugs on a 114.3mm circle.
Common bolt patterns:
- 5x114.3 — Most Asian and American sedans/SUVs (Honda, Toyota, Ford, Nissan)
- 5x120 — BMW, some Mercedes, Jaguar
- 5x112 — Most Mercedes-Benz, Audi
- 6x135 — Ford F-150, Expedition
- 6x139.7 — Chevy, GMC, Toyota Tacoma, Nissan Titan
- 8x170 — Ford Super Duty (F-250, F-350)
- 8x180 — Chevy/GMC 2500, 3500
Offset (ET)
Offset is the distance in millimeters between the wheel's mounting surface and its centerline. It's designated as ET (Einpresstiefe in German) followed by a number.
- Positive offset (+35, +40): Mounting surface is toward the front (outside) of the wheel. Most front-wheel-drive and modern cars use positive offset.
- Zero offset (ET0): Mounting surface is at the centerline. Common on older rear-wheel-drive cars.
- Negative offset (-12, -25): Mounting surface is toward the back (inside) of the wheel. Creates a deeper dish look, common on trucks and off-road vehicles.
Changing offset affects track width, steering feel, and suspension geometry. Stick close to factory offset unless you understand the implications.
Center Bore
The center bore is the hole in the middle of the wheel that fits over the hub. Hub-centric wheels match the hub diameter exactly, ensuring the wheel is perfectly centered. Lug-centric wheels rely on the lug nuts for centering.
If the center bore is larger than your hub, you need hub-centric rings to fill the gap. Running without rings can cause vibration at highway speeds.
Backspacing
Backspacing is the distance from the mounting surface to the back edge of the wheel. It's related to offset but also depends on wheel width. More backspacing means the wheel sits further inward.
Putting It All Together
When ordering wheels, you need: diameter, width, bolt pattern, offset, and center bore. If you're unsure about any of these, contact us at support@nextautopart.com with your vehicle details and we'll help you find the right specifications.
