I was rear-ended in the '97 Stratus on the freeway and pushed into the car in front of me, a few days after I'd replaced the donut spare with a full-sized wheel and tire. I think that the spare effectively saved the quarter panels from buckling. The rear bumper's core of foam or plastic or whatever it was pushed into the spare tire well, which slightly deformed as it pushed into the tire, and the tire slid just a bit until it made contact with the front part of the well, and then the tire squeezed just a bit, and that was that. Had the donut been there I expect that the rear-quarter of the car would have tweaked under the C-pillars and that it simply would have been totalled. The body shop was able to pound the spare tire well back out, repair the trailing edge of the trunk opening, and replace the rear bumper cover and bumper insert.JavelinAMX said:I like capable full-sized tires - build the space to carry it. Placed correctly, that could aid rear-end collision protection. But designers would have to be given 'leave' to leverage that sort of thing.