The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - -20mm offset rims on 8 lug

**Dashman** · 03-20-2024, 07:22 PM

The back spacing and the offset don't correlate. If the wheel is 8" wide and the back spacing is 3.71", then there is 0.29" to the centerline. 0.29" is 7.36mm, or -7mm offset, not -20mm. The conversion is 1"/25.4mm or 25.4mm/1" depending on which units you want. Those are like factory wheels. It's the 12.5" section width that may cause some interference while turning depending on your lift. That tire will be out (12.5-8)/2 or 2.25" per side. You could actually measure out from Wheel Mounting Surface (8-3.71) +2.25 = 6.54" to get an approximate edge of tire section.

03-20-2024, 07:22 PM	#8
Dashman Junior Member Join Date: Apr 2021 Location: Santa Cruz, NM Posts: 58	Re: -20mm offset rims on 8 lug The back spacing and the offset don't correlate. If the wheel is 8" wide and the back spacing is 3.71", then there is 0.29" to the centerline. 0.29" is 7.36mm, or -7mm offset, not -20mm. The conversion is 1"/25.4mm or 25.4mm/1" depending on which units you want. Those are like factory wheels. It's the 12.5" section width that may cause some interference while turning depending on your lift. That tire will be out (12.5-8)/2 or 2.25" per side. You could actually measure out from Wheel Mounting Surface (8-3.71) +2.25 = 6.54" to get an approximate edge of tire section.