When I first changed to 15 inch wheels, I tried some used tires......two of which just threw the tread after about a month of little mileage. So, I ordered some inexpensive tires on the amazon. And, my local small shop installed on my new rally wheels. After about ten months, flat tire due to a cracked valve stem. Today, I find another flat, and another cracked stem. Is it not interesting what we have done to ourselves. I will try the auto shop stems this time, and use them for replace.....and am confident of nothing at this point.