Is it true that "normal" "king sized" or "double" mattresses don't fit IKEA bed frames? Reason I ask is I've just bought 2 new beds, but want to keep our old mattresses. I measured the mattresses before leaving home and the double is 140 x 200 and the king sized is 160 x 200. IKEA gives the same measurements so I think they should fit? But heard lots of people in there talking about how only IKEA mattresses go on IKEA beds.
I don't want to have to pay the delivery charge twice so if I need to buy mattresses as well I should do it now.
Has anyone had this problem?