A friend of mine tried this, even though I told him it wouldn't work. He basically did the same thing as the OP. Within a week he had spider cracks, 2 weeks and small pieces of paint were flaking off, three weeks later he sanded them back down to the black rubber, had them flipped inside out, and shaved the thin white walls into wider whitewalls like I told him to do in the first place and has had no problems with them in about 5 years of driving everyday.
I stripped all the paint off, and am going smooth blackwalls now. I Didn't feel like busting the tires off again, so I just aired them down. You can see it is still a little white stained around the wheels. In retrospect, I don't think whitewalls fit the look of my truck at all. Sort of a before and after:
http://youtu.be/pHWTa2tAYIc <iframe width="425" height="349" src="http://www.youtube.com/embed/pHWTa2tAYIc" frameborder="0" allowfullscreen></iframe>
I wonder if you had lower profile tires with the skinny strip and you sanded them if it would make them look wider because there is less black showing??? just a thought
The Jalopy Journal
