If I recall correctly, the thread size is large, approximately 11 mm. People found it just about impossible to source stateside. I tapped mine to fit a 7/16-28 bolt. Holds my cargo drawers just fine. Empty the drawers/sleeping plateform weigh about 80 lbs., filled about 160 lbs. Never had a problem over bouncy terrain, but I have never rolled it either. Just my $0.02
Chris D.
Mudy_ovl