Popular Mechanics, heinäkuu 1928
Many persons have been mystified by the presence of a small red spot on the side of balloon tires. The mark looks as though a drop of paint had been splashed on the rubber by mistake, but there is nothing careless about it. In fact it has been placed to show exactly where the valve should be fixed in order to maintain balance in the tire. This is done to prevent "shimmying," the weight of the valve being sufficient tot throw the tire out of balance if it is wrongly located. The mark is made on the lighter side of the casing.