Originally Posted by
Nightshade
Must've been really crappy steel in that eye bolt or you loaded it wrong. Either way the way mine are installed the load is on the shaft not the eye.
I have trouble imagining how you load the eye bolts such that there's no load trying to straighten out the bolt.
Looking at this table:
http://www.smithfast.com/eyebolt5_6.htm
Perhaps a 3/8 bolt would be reasonable for a 2x4? They give a maximum vertical load of 1400 pounds, assuming "a straight vertical lift in a gradually increasing manner". Which a trailer on potholes won't be providing. Hmm.