Why would a vehicle fail inspection if the vehicle has radial tires?

A vehicle would fail inspection due to the presence of radial tires if they are mixed with bias ply tires. This mismatch can lead to handling issues, uneven tire wear, and compromised stability, which are significant safety concerns. The design and construction differences between radial and bias ply tires affect performance characteristics, particularly during cornering, braking, and overall driving stability.

When tires do not match in type (e.g., radial vs. bias ply), the vehicle may experience inconsistent traction, which can be dangerous. It is critical for safe vehicle operation that all tires are compatible and intended for the same performance requirements.

While tire matching generally addresses aspects such as tread pattern and size for balanced performance, the most important factor in this context is the type of construction—radial versus bias ply—as this fundamentally influences how the tires interact with the road and with each other. If inspection reveals a mix of these tire types, it would lead to an automatic failure for the safety of the vehicle operation.