I've got an enclosed 6x14, single axle. Can fit 4 sport bikes with room for gear. I need to make some shelves up in the V and it would be better. If I had to do it all over again I would go with a 7 ft wide trailer. It gets tight between the bikes in a 6 ft. I tow with an F150, and doesn't really matter the load, it gets ~11 mpg towing that trailer. Could have 4 bikes and loaded to the max with gear, or could be empty. It has more to do with the fact your pulling a giant sail behind you. I also tend to drive fast, I could probably get 13 or so mpg if I went 65 on the highyway, but I choose to go closer to 75.