Nice!! I have brackets that attach to my Pitbull chocks that were made by my local trailer place. They clip into the etrack. But, as you stated, I had to mount a piece of etrack perpendicular to the length of the trailer. That works for me, as I only ever carry two bikes, but your solution for front-to-back adjustability is excellent! Thanks for sharing. Many have asked about this. The brackets I have would work nicely, then I could use your set up for the "mobile etrack". I'll keep that in mind if I ever decide I need the front-to-back adjustability. Cool!