US safety regulators have opened a defect investigation into 384,608 General Motors’ full-sized pickups and SUVs from the 1999-2003 model years, the safety agency said on Monday, according to Reuters.

The “preliminary evaluation” by the National Highway Traffic Safety Administration, or NHTSA, covers the Chevrolet Silverado and GMC Sierra pickup, and the Chevrolet Tahoe, Chevrolet Suburban and GMC Yukon SUVs, Reuters said, citing the NHTSA. The agency has received two complaints of cracked steel wheels, the report noted.

According to Reuters, the evaluation covers the pickups and SUVs equipped with six bolt 16-inch-by-6.5-inch full-face steel wheels though most of the pickups and SUVs were sold with aluminium wheels.

GM spokesman Jim Schell told Reuters the complaints charged that the cracked wheels caused a slow leak in the tyres.

“There’s no risk of motor vehicle safety,” Schell reportedly said, adding that GM was cooperating with the investigation.

According to Reuters, NHTSA will look into the complaints further before deciding whether to upgrade the investigation into a more serious “engineering analysis” or to drop the inquiry.