Re: 2007 rockwood tent trailer poor quality mattress
Memory foam might make it more comfortable, but probably won't affect any 'crunch'.
The only thing I can think of which would 'crunch' would be some kind of wrapper around the mattress, or something crunch beneath the mattress. Check this out.
If nothing on or under the matteress is causing the noise, make the dealer lie on it and move around. That may result in some action. If not, buy a mattress you like; sleep is too important to 'cheap out' on.