The Stovebolt Site Forums The Parking Lot Big Bolts 8 to 10 lug adapter specs

Good afternoon! I am currently working on a 1966 Chevy C60 project. Putting the cab on a 1998 GMC Savana 3500 dually chassis. I would like to go from the 8 lug pattern to a 10 lug to be able to run 22.5" alcoa wheels on it.

I work for a machine shop that could make me adapters if I knew what dimensions the adapter needs to be. So far I have the center bore size, both 8 and 10 lug pattern size and thickness. I just need to know what the outer bore size should be.

Anyone know where I would find this information? I've come across several different styles of these adapters but haven't been able to find the dimension specs.

Thanks in advance!

Hy kscholtus66C60, welcome, I don't understand "outer bore", do you mean the outside diameter of the wheel mounting flange or what would be the hub diameter on a truck using the 22.5 Alcoa's?

The bore of a standard 22.5 hub piloted wheel is 220 mm. The bolt circle is 285.75 mm and the studs are 22 mm. That should allow plenty of room to make an adapter.

Sometimes in doing this, the two bolt circles do not have enough room between them. An option I used was to put the heads of the smaller bolt pattern on the inside using Allen head bolts(grade 9) on hub centered axles. Then there is plenty of room on the outside for the larger bolt pattern. I used steel for the plate. 5 on 8” on outside, 8 on 6.5” on inside.

Ed

I just bought adapters and can measure the outer diameter if that is what you need.