I don't remember the dimensions, but they matched the Chevy 6-bolt pattern. Mine started to show stress cracks in the cutout pattern of the rim, double check the ones you are buying do not show the same. I replaced mine with Raceline rims which were available in a higher rating with the same bolt pattern.
The OEM rims were rated for around 2500 lbs and had a 6x5.5 bolt pattern.
Host Mammoth 11.5 on Ram 5500 HD