I bought two new 4.80 x 8.00 tires and rims a few months ago. They probably have less than 200 miles on them. I noticed yesterday there are splits in the sidewalls. One tire has several and using a straight pin I found that one is 1/8 in deep. The splits run perpendicular to the rotation. Some are over 2 inches long. Does anyone know what the cause could be.<br />Thanks