Lots of folks do this on GL1800 Goldwings. I don't know any who have had any problems so far doing it.
BUT:
Maybe it's me but after talking to a few people in the tire business I have decided that this is not the safest way to go. Some people could give a rats ass about safety and ride all kinds of stuff that I would not even try like no front brakes, just because they have survived so far even with thousands of miles does not make it a good idea. The sidewalls are completely different on a car tire and a motorcycle tire. I am not talking about riding on the sidewall, I am talkin about pressure on the sidewall while cornering. A car tire is not meant to roll leaned over and is not designed to do so. You ever seen a car tire fold in during a high speed slolem cornering manuveur? I have. Just think, those tires are on rims that are standing up 90 degrees to the pavement, so this is at least double as likely when on a 45 degree angle. Simple physics. The myth about tire manufacturers just trying to gain extra profit off motorcyclists is obserd, the cost is not just the materials but also in the R&D to create the thing...........I would not do it........just my two cents. Might be ok for an old guy who basically never hits corners on a highway on a goldwing or other 6 cylinder beast. You guys try it and let me know how it goes.