Car tires are not engineered MC's & motorcycle tires are not engineered for cars, they don't look anything alike...… The DOT rating is for what the tire was designed to fit, nothing else. I'll bet you'll never get a car tire mfg. to give you something in writing that says it's even "OKAY" mount it, much less ride with it. ……. Heck, why not put a car tire on the front too?? Makes as much sense as putting one on the rear...… Will your insurance cover you if you crash, or will you be stuck with the entire bill for both vehicles, no matter who's at fault ?? All it'll take is a sharp eyed adjuster.....your money, your bike, your life...………. just saying