My local hardware store only carries grade 5 in the 1/2" size bolt I was looking for I asked for grade 8 but they only carried 9/16 and 3/8 in grade 8. Now I am using these 4 grade 5 bolts to mount my class III to my frame. Should I be worried about these things sheering off? I wouldn't think so but everyone swears by grade 8 stuff. Just scary thoughts cross my mind as the guy told me I wouldn't tow any more than two tons. Wheeling and using the hitch for a recovery point I am sure the stress can reach near and over that of two tons. Whats the real specs behind the integrety of the two and is there really that big of a difference?