Reason for limited matress thickness in Sportsmobile PH Roof?

Hello all! I am relatively new to the forum and have become obsessed with Sportsmobiles. I love the idea of compact luxury that can take you many places other coaches can't.

I haven't actually seen one in person (hope to sometime later this year). But one of the things I'm particularly interested in is the comfort of the sleeping in the PH top. I've seen that some people add a 2" memory foam mattress with good results.

My question is this: why only 2"? I have read that there isn't much more space than that once the roof is down. But why is that? Does the bed attach to the roof of the PH (and then get released once the penthouse is raised)? Or is it attached even with the regular roof of the vehicle? Can't quite visualize it in my mind (even with all the pictures I've seen). Guess I'll just have to go see one in the wild.

Any information would be much appreciated. Thank you!

There is a really good thread on the Sportsmobile and the transition.  Do search on the Sportsmobile, it ought to show up. 

Thanks, PancakeBill. Transition is the word I was missing. I'll take a look.

Sportsmobile Penthouse Raised Roof

this is the name of the thread.  Shows conversion and some mods.

I went out w a pencil and block of wood as a story stick and did some rough measurements.

The clearance from the underside of the penthouse roof to the bed rail (~ top surface of bed platform) is ~4 3/4 inches.

The boxes that hold/contain the roof support tubes are 1 1/2 inches thick.  Subtracting this the clearance is reduced to 3 1/4 inches.

Sportsmobile has two chromed handles to grab to lower and raise the roof.  These handles stand 1 1/4 inches proud of the above mentioned boxes.  Subtracting this the clearance is reduced to 2 inches between the bed platform and the closest point on these handles.  A 2 inch thick mattress would just eat up this space.

The bed does need to slide back and forth on the bed rails so that after lowering the top (using the handles) the bed can be slid forward (hiding the handles) exposing the roof rear tie down hardware so the roof rear can be secured.

I personally see no reason why the chromed handles could not be replaced with heavy webbing straps.  Should work the same and give another inch of space for bedding and or thicker mattress. 

Will know more about a week.  Have found that Thermarest now has 2 inch thick mattresses that are 20 inches wide.  Have two on order.  Two of those will fit nicely on our 40 inch wide bed platform.  We wedged our two 25 inch wide 2 inch thick Thermarests when we used our van this last weekend.  Slept fine but was a fight to get them into the 40 inch space.

Will have to open a Thermarest store.  Still have two 3/4 inch shorties from backpacking days, two 1 inch thick full size ones from our canoing days.  Now we will also have two extra large base camp ones floating around.  But then...maybe....maybe.... I will get out the backpack again....maybe.  In my dreams.  The van is SO MUCH easier on the body and SO MUCH drier in the rain.

Wow! Len and Jo, thank you so much for your reply, this is incredibly detailed and useful information! While I don't mind roughing it and enjoy dropping a tent on the ground, I like the idea of extended trips in rougher weather with all the comforts of home. And sleeping comfortably is just one of those must-haves for me. So the sleeping options are important to me.

Given your experience with the van, would it ever make sense to drop the bed platform lower? It would require a modification, of course, so that the attachment to the rails allowed the bed to move back and forth still. This would reduce headspace but increase the amount of mattress space in the PH.

I know, I know, if I need that much mattress, maybe I should get a hotel room. But again, this is a priority to me. Where others might spend more and make mods to install hot water or massive sound systems, I would put a bit more into the sleeping arrangements.

Any thoughts or suggestions would be appreciated. Thanks again!

We find our 2" thick Basecamp Thermarest pads to very adequate for sleeping.  We made our own bed platform out of 3/4 inch cabinet grade plywood.  I doubled the thickness at the edges and this gives us 1 more inch of head clearance when the roof is down.  We get about the same clearance as when the original OEM roof was still on.  It would be easy enough add any reinforcement to a 3/4 inch bed platform INSIDE of the Penthouse roof bed rails.  Thus you would get more mattress thickness room but would lose same amount of head room when using the space under the bed.

Again we find a good 2" mattress OK.

Len and Jo, again, thank you so much for your insight. I don't own an SMB now but have become obsessed since I first saw one. Looking forward to learning all I can while saving money to get one. I appreciate your insights.