The mattresses provided by Thor in our Axis 25.5 were overly hard and miserable, especially for our bad backs. We tried adding memory foam pads which didn't help much. In desperation, after waking up with sore backs after our first few trips, I removed the junk provided by Thor and, after some measuring, put in the twin bed mattresses from our guestroom. These worked perfectly. The twins were about 4" wider than the Thor junk, so I cut 2 5/8" pieces of plywood, 77" long, covered them with some dark gray felt from Walmart and bolted them to the bed bases. They are perfect. We did add 4" memory foam pads to both and now the beds in our Axis are more comfortable than our bed in our home. We only lost about 6" of isle space between the beds, which leaves us plenty of space to get to the bathroom, etc. Obviously, this mod eliminated the option to converting to a large king-size bed but as miserable as the Thor bed pads were, we'd never have used this option anyway. We'll store the Thor junk and, if a future buyer of our Axis want them, reinstall it.