Core: Load, licence plate and view
Licence plate, lighting, view, trailer — four requirements load may never break. If the bikes cover the plate, a repeater plate is needed. If load covers the lights, move them or use a lighting bar. All mirrors — inside mirror and both outside mirrors (or equivalent camera systems) — must stay usable. And as soon as a wide trailer or caravan blocks your rearward view through the normal outside mirrors, you must fit extra outside mirrors.