Tangent spokes.
One point must not be forgotten in this matter, which redounds to the credit of the absolute direct spoke. It is that the driving strain passes through every spoke from the hub to the rim, whereas, in a tangent or partial tangent spoke, the strain is resisted by only one-half of the entire number. This defect is partially remedied by the late plan of soldering the spokes together at the points of crossing, this binding together being what really makes the tangent spokes so strong in resisting buckling, to which they were very liable before the soldering process was used. I am inclined to think that the midway or partial tangent hubs are the best, as they seem to combine all of the possible advantages, but the plan of crossing the spokes just once is, in the light of my experience, very bad, as it seems to combine the faults of both with the advantages of neither; they should be more nearly full tangent than direct if varied from the midway position at all. The small eighteen- or even thirty-inch wheel is good enough, if well made, with either direct or tangent hubs, especially in the one not used as a driver.
Old bone-shaker wheel.
The soldering of the spokes together, and other difficulties in the way of screwing them into tangent hubs, has led makers to adopt the plan of screwing them into the rim; this seems unavoidable, but is not very desirable, if for no other reason than that the wheel getting wet, the screw threads are apt to rust off and strip. With brass, aluminum, or bronze nipples, however, this difficulty can be to a great extent overcome.
Tangent wheels are as old as the industry of cycling. Starley, of Coventry, is said to have experimented and shown, many years ago, that a tangent wheel with silk spokes would resist the revolving strain on the hub equal to a direct wire spoke, and the Scientific American gave an illustration of a tangent hub in their issue of September 1, 1877.
The cross bar in the old bone-shaker made practically two tangent spokes, and pulled from the rim, so to speak, as will be noticed in our essay on hobbies.
CHAPTER XX.
ANTIFRICTION BEARINGS, BALL AND ROLLER.
The cycle art has developed the use of antifriction, or, we might say, rolling-friction bearings, to an extent never before attained; these bearings are in the form of balls and rollers; the former are made in several styles and the latter in at least two, but all are more or less old in the arts.