Hitch bolt size

[GN4HIR]

Quick question that search didn't answer. The bottom two holes on the flange of the hitch are threaded and in some markets that is where the ball is attached. I'm planning to use those two bottom holes as the attachment point for a step. Can anyone confirm the bolt size and thread pitch? I suspect it is M16 2.0 but I may be wrong.

Thank you for your assistance.

 

[RayMe]

Did you ever get an answer to this? I’m planning a similar move and the bolt holes are larger than my fastener sizing tools….

 

[TD5-90]

Did you ever get an answer to this? I’m planning a similar move and the bolt holes are larger than my fastener sizing tools….

Correct, M16x2.0 10.9 .
According to my dealer, torqued to 280Nm (dry), lock washers appearingly similar to this type.
I personally think the specced torque is relatively high with the slim weld nuts that have seen substantial heat during assembly of the hitch block.

 

[landmannnn]

For some reason mine has 12.9 graded bolts.

 

[C-Mack]

The top four are M12 x 1.75 and I bottom two are M16 x 2.0 as others have commented.