Outer Limits 4x4 Board

....... inside dimensions? See I wanna fit my 1230mm wide roof tent inside a mates roofrack that is located away from both our houses and not easily get-at-able. The cotelogue states it's 1250mm.
TIA
Jonesy

even if its outer measurements, would the bars be more than 10mm wide? if not, then it will fit snug as a bug in a rug

My gq shorty rack measures 1250 between the bottom rails, and measures 1270 at the uprights (which is what limits the width)

Thanks & thanks.
But I need a bit of slack as the tent folds down on itselt & like anything else seems to never fit in back in its origional bag. But going off the 1250inside dimensions of the GQ I reckon the one in question will be thesame. I'll let you know.
Jonesy