C172 can be rolled very nicely by a properly trained pilot, I have done it. I regularly loop and roll my C150 (and before the outcries begin, it is equipped with an accelerometer). Those without training for this should not attemp, for reasons given above.
I once asked a friend, while enroute with him in his Cessna 185 amphibian, if it could be rolled with all of that weight down there. He said that he did not know. Now we both do, it will roll very nicely! While teaching me one day, he demonstrated a perfect 8 point hesitation roll in his C182. The maps on the back seat did not move. He is a pilot with skill beyond mine.
Training, training, training!
Pilot DAR