the frames have to be different, because the right side case and the tub haven't gotten any closer together than they were on the original model
i now know (because Barry measured it for me) that the whole rig is 79.8" wide from left side case (and left mirror of my GS-Adventure) and the fender of the sidecar
which is 4" wider than you thought it would be, i believe, elmer
which is, by the way.... an INCH WIDER THAN MY NISSAN ARMADA...
'07 K1200 GT
'11 R1200 GS Adventure with a DMC M72DX Sidecar
live life like you mean it... but take your family and friends (and DOGS) along for the "ride"