Two important things on a friction drive set up. Make sure the drive roller is absolutely perpendicular (90 degrees) to the wheel/tire. Use tires with little or no tread, especially in the center where the roller contacts the tire. I found using very expensive tires is a waste of money. Because the tire flexes both when it contacts the road and then a great deal more when it is deflected under the roller, the tread will separate on the sides. Very cheap tires aren't worth the time and trouble of replacing them. Use a mid priced tire.