5x5
Bolt pattern for a 1985 GMC Sierra Classic 1500 is 6x5.5 (That is what mine is)
6x137.5
6x5.5
8x6.5
6x5.5
6x5.5
6 x 5.5
six on 5.5 chipc@kovach.net
K1500 is 6-139.7mm/6-5.5"
should be 6 x 5.5
GMC has three different bolt patterns: The Acadia has a 6X132 the Envoy has 6X135 and the full size such as Yukon and Sierra which have 6X139. Hope this helps you.
4.52" backspacing -12mm offset 16X7 6 on 139mm bolt pattern