Looks just like the bubble we had on a buddy's Unimog, except his was the size of a softball, we actually had a cop pull us over because of it. I just LOVE changing 44" tires on 20" steel military rims, a nice 200+lbs each......and the spare is on his radio box's roof..... 10ft up :-(
I wouldn't try driving too far on it.
I got your JEEP thing, now it hurts when I pee!!