Which inspection method should be used to detect cracks on the bead seat area?

• A. Ultrasonic
• B. Magnetic particle
• C. Eddy current
• D. Dye penetrant

Answer: (C)

Bead seat cracks are usually shallow, surface-breaking defects in the rim where the tire bead seats. You want a method that is highly sensitive to tiny near-surface flaws in a conductive material and can inspect curved, complex geometry quickly without disassembly. Eddy current testing does exactly that: it induces currents near the surface and detects disturbances caused by cracks. This makes it ideal for aluminum wheel bead seat areas, where magnetizing methods won’t work well (aluminum isn’t ferromagnetic) and dye penetrant would require surface preparation and may not suit the whole seating area. Ultrasonic can detect cracks too, but on curved rims it’s more challenging to couple and interpret, whereas eddy current provides fast, sensitive detection of near-surface cracks in this context.