The Classic Haulers is just wrong. It looks poorly formed too.

 

Maybe failure is rare, don't really know for sure, but I still want good ole' U.S. of A. cold rolled steel for critical fasteners. Those black ones in the pic just have that HF paint job look, from golly knows where, made from who knows what. Good U bolts have rolled, not cut threads if you can believe that.

http://www.portlandbolt.com/technica...threads-bolts/

Also check to see that replacements on the shoulders have the correct radius or whatever - "semi-round" or "square" as required. They will loosen up at best if the wrong ones are installed. Loose U-bolts means broken leaves.