What size is the chevy express lug nut ?

The wheel lug nuts for the Chevrolet Express may vary in hex head size between model years and configurations. It's also important to note that previous owners may have upgraded them with aftermarket equipment that affects head diameter and overall length, but thread size should always remain constant. The stock lug nuts will always have M14 X1.50 thread. Most will typically have 22mm hex heads, though some measured 13/16 inches. The overall length varies between 20.5mm and 28.5mm, though this isn't very important in the big picture. Your bolt pattern indicates that each wheel will use SRX lug nuts, and each has a torque spec of 190 Nm. It's important to always ensure that this specification is met for optimal safety for the driver and others.