the current track is 57" . I plan on "hacking " the frame off and pulling the suspension in to the end of the cross barace . 53 or under is my goal depending on wht the pups can lounge in without discomfort during long stretches of travel. We mocked up a car body last night out of scraps of angle so we can get the pups in it and really see the space they are gonna need and try and get a feel for weight distribution. I'm thinking I can squeeze them into a much narrower car than the wifey is leading me into .