I found a simple modification to the rear rack bike set-up on many FR TT and 5ers. After removing the eye bolt, the working end of an Allen 522rr (Walmart) will slide right over the tube. Mine was a little indented where the holes were made and I did have to pound this out to make a fit. I also enlarged the hole for the pin to 3/8" which reduced wobble. I also cut the tube that came with the trailer down (with my Dremel) so that the bike wheels sat down below the rack rails for more security.
This is easy to load and seems secure. I'm not happy with the weld on the rack that holds it all on but so far it has held. The other nice thing is that I can quickly attach this back to the hitch receiver assembly and just use it as a normal bike rack too.
That's good advice, however the way that the bikes sit with wheels down in the FR installed platform, with a couple bungies to secure things forward all that will happen with a failed weld will be a drop of about 3 inches. That's what makes this mod particularly attractive.