Bolt Pattern and Bore Size (all) - 6x139.7 or 6x5.5 and the Hub Bore Size is 100.3 Factory Wheel Specs 2004-08 Z85 Steel Wheels 15 x 6 Offset ? 2009+ Z85 Steel Wheels 16 x 6 Offset +23mm 2004-08 Z85 Alum Wheels 15 x 6.5 Offset +23mm 2009+ Z85 Alum Wheels 16 x ? Offset = ? 2004-08 Z71...