MATERIALS OF CONSTRUCTION. The surface of , a bicycle-race track may be loam, clay, cinders, wood, or cement.
Most of the early tracks were constructed of either loam or clay. Such surfaces are cheap and easy to construct; but on the other hand, (1) the cost of maintenance is great, (2) high banking can not be used, and (3) moisture destroys temporarily the usefulness of the track. The Hampden Park track was constructed of clay cov ered with a thin layer of brick dust, and at one time was very popular, owing chiefly to its excellent surface.
A well constructed wooden surface is very fast, and for this reason has been used in many short tracks, in which high banking is required. An example of such construction is the Colosseum track at Springfield, Mass. The surface consists of strips, one inch square, nailed to a foundation of 2" X10" timbers. In-doors, where tracks are frequently constructed for temporary use, wood has decided advantages; but for out-door use wooden tracks are uneconomical, because of the destructive action of the elements.
In most of the larger tracks lately constructed, cement surfaces have been used. Such a surface is practically indestructible, and hence there is no expense for maintenance. Its usefulness is not destroyed by moisture, and any degree of smoothness may be ob tained. Cement was used in the construction of the Waltham, the Louisville, the Manhattan, the Garfield Park, and the Racine tracks. The surface of the Manhattan track is most nearly ideal and for that reason will be described somewhat in detail. As is shown in Fig.
171, page 646, the embankment of the Manhattan track is com posed of four distinct layers: 1, a gravel embankment; 2, an g-inch layer of ash concrete ; 3, a 3-inch layer of crushed granite concrete ; and, 4, a top layer of 11 inches of cement mortar. The gravel was deposited in thin layers and thoroughly compacted by rolling. The ash concrete, whose purpose is to protect the gravel embankment from washouts and from injury by frost, consists of Portland cement and ashes in the ratio of 1 to 8 or 10. The 3-inch layer of granite concrete is composed of one part of sand, one part of Portland cement, and seven parts of crushed granite. The top layer consists of 11 inches of mortar composed of one part Portland cement, one part sand, and two parts of powdered granite. Lampblack was mixed with the cement mortar to prevent the glare of the sun. The surface of the mortar was roughened by special tools to prevent the slipping of the tires. Special care was taken that the interstices between the blocks of concrete should not be so wide as to impart a vibration to the bicycle. The surface of this track has withstood the test of actual service, as well as the weathering of several years, and has proved itself very satisfactory.
A novel feature of this track is the four parallel black guide-lines, each four inches wide, painted on the surface of the track. A racer riding at full speed with his head bent down over the handle bars does not notice that he is approaching the curve, and if he does not guide his wheel accordingly he will run off the track. The guide-lines warn him as he approaches the curves and thus prevent an accident.