Wheel concavity refers to the wheel face curvature profile on a monoblock (one-piece) wheel or wheel center on a modular wheel. Concavity is different from “dish depth” on a modular wheel. When looking from the side, a wheel with large concavity has a wheel center that’s sunk in. A wheel with no concavity has a wheel face profile that’s flat. Lots OEM wheels have a flat face profile.
For off-the-shelve flow formed or cast wheels, the face concavity is pre-set. What you see in the picture is what you are getting. You can ask the wheel manufacturer to confirm if their wheel design is suitable for your vehicle. For bespoke-made forged wheels, wheel face concavity depends on three factors: wheel width, offset, and brake clearance.
Wheel width and offset together determine where the wheel mounting hub would be, and the depth in relation to the wheel face. A wheel in 20x8.5 ET+35 will appear to have a flatter face profile (less concavity) than a wheel in 20x12 ET+35.
A wheel in 20x10 ET+15 will look much more concave than a wheel in 20x10 ET+50 because the mounting hub is 35mm closer to the wheel center line (dip inwards).
A wheel made for cars with small brake calipers can typically have more concavity than cars with big brake calipers. for example: on high-performance cars. The front wheels usually have less concavity because the front brake calipers are usually bigger, and the wheel face profile needs to be flatter to clear the brakes.
You can tell the wheel face profile difference easily from the two pictures below. The rear wheel has more concavity compared to the front wheel.
As stated above, these factors affect how the wheel profile looks and poses physical constraints on what can be achieved while providing the best fitment. At Forgelite Wheels, we design each set of wheels with the proper brake clearance and maximum concavity that greatly enhances your vehicle’s appearance. In addition, we send wheel renders before putting them into production so you know how the wheels will look when they are finished.