[DutchmenSport]

Not a problem with a heavier mattress. We replaced ours (our bedroom is in the rear though, bed on a cable driven slide) with a Helix Mattress. (Absolutely not cheap). It's 12 inches thick of solid foam, heavy as a house.

There is a down-side to swapping out the factory mattress for a heavier, thicker, better one .... and that is the fact, if you have storage area under the bed, lifting the access door lid and the heavier mattress can be a real challenge. If you have struts under your bed, then I strongly advise replacing those struts with much stronger ones, because it takes both of us to get under the bed now. One to lift and hold it up, the other to dig inside to find what we need or want, or to store something else. One person by themselves? It's a challenge that I can't win.