Marking point for the valve stem. These tires are so perfectly balanced that the weight of the valve stem is allowed and provided for. This woman attaches a label to the tire at the point where the valve stem should be placed. Balancing a tire was once considered unneccessary, until it was demonstrated that out-of-balance tires cause wheel shimmy, excessive wear and many other tire evils. Firestone (General) Tires, Akron, Ohio