Page:The Cycle Industry (1921).djvu/23

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than ball bearings. Bown then, or Green, brought out a bearing which consisted of a grooved cone and two cups, the grooves in all three being slightly wider in radius than the diameter of the ball. When wear took place the cups or one cup were screwed inwards and relocked. These were separate proprietary articles and were attached to the fork of a bicycle by cotters and nuts. The rear wheel was provided with a slightly different type of ball bearing, the adjustment being effected by screwing the cones or one cone inwards instead of the cup or cups. Subsequently ball bearings were applied to the steering and the pedals, but an indication of their importance may be gained by the fact that for a long time the manufacturers catalogued their machines with plain bearing pedals and charged 30s. extra for ball pedals.

We have now arrived at the stage when a high bicycle was regarded as dangerous, and, if the front wheel were too small, it detracted from the rider’s speed owing to the shorter distance covered by each turn of the wheel. What was the next move? The engineer’s mind turned towards a method of gearing by cogs or chains, by which one turn of the crank axle would cause the driven wheel to turn more than once. That is where we get our method of describing the ratio of gearing between the crank and the wheel of a modern safety bicycle. The previous machines had wheels, say, from 50 ins. to 60 ins. in diameter or height from the ground. Now supposing you took a 25-in. and a 30-in. wheel and by means of gearing made them turn twice to each turn of the pedals and cranks, they would be equal to 50-in. and 60-in. wheels—without gearing—that is why we still speak of a bicycle with 28-in. wheel being geared up to, say, 56 ins. when it travels as far