“Z71” is a Regular Production Option, or RPO, code that U.S. automaker General Motors uses for its off-road suspension package. This particular option is most famously associated with vehicles out of GM’s Chevrolet division.
Z71 Off-Road and Suspension Enhancements
The major feature of the Z71 package is its enhancements for a vehicle’s off-road capabilities, including bigger wheels — specifically, 18-inch aluminum wheels — which are fitted with on- or off-road blackwall tires. The Z71 offers specially tuned springs and mono-tube shocks for the suspension to better support the vehicle’s weight and tire contact, as well as further dampen shock. This is combined with an automatic locking rear differential to improve the distribution of drive shaft power.