OK guys, I'm claiming some sort of record here - this design is posted 23hrs after Petman (got a name?) first posted!
It's a sorta square, with a Jim Dandy front end, a drop-down ramp at the back and a lift-up top. This works as shown but it could do with at least one more loop around the design spiral. Body is 8ft long, 5ft wide, 4ft high. Wheels are 8" (scooter wheels for a scooter trailer, eh?) to keep the trailer near the ground - that gives 540kg (1200lb) on 4-ply tyres and 680kg (1500lb) on 6-ply.
The interior is a tight fit on a standard
Gilera Runner, so if your bikes are any longer than standard (they won't be taller, eh?), the galley needs to get smaller. The roof is shown lifted a bit, but rather than hinge it, I would make it a lift-off panel.
The frame consists of a triangle (axle + A-frame) in 50mm SHS and the rest in 50mm angle. Sorry, Merkans, this is another a' them gosh-darn metric designs. Posts up the sides at the back will stop the roof-less box from wobbling too much - an idea stolen from British horse-boxes!
All three drawings in a pdf file. The grid squares are 250mm.
Whaddya all think?
Andrew