Читать книгу The Modern Bicycle and Its Accessories - Julius Wilcox - Страница 33

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The riders of Humber bicycles now have an opportunity of experimenting at comparatively small cost, because the makers of the Humber will convert an 1898 chain Humber into a Humber Chainless for $40, an 1897 for $50 and an 1896 for $65, or they will convert an 1898 Humber Chainless into a Humber chain cycle for $18 at any time during the season of 1898, should the buyer not be satisfied with the chainless, which is thought highly improbable, because the cycles they have made for testing purposes run easily and smoothly and have proven strong and durable under severe usage.

HUMBER CHAINLESS.

The makers of the Humber Chainless do not claim that it runs more easily than the chain Humber, the chain of which is accurately made and the sprockets accurately cut. Nor do they claim that the gears will not wear in time. It is customary in all well regulated factories to write off 10 per cent. each year for wear and tear on machinery, but they are sure that the spur gear chainless runs easily, is simple of construction and adjustment, and is not likely to get out of order. The details of the construction of this model do not differ from the regulation chain model.

The front gear is 10¾ inches in diameter and has 126 teeth. The rear gear is 4½ inches in diameter and has 50 teeth. Between them is an intermediate and connecting gear of 11 inches in diameter, with 127 teeth. The resulting gear ratio is 70. As two large gears of 125 teeth each will produce an exact ratio of 70, this uneven combination is intended to lessen the frequency of contact between the same teeth, on the “odd-tooth” rule of mechanics. The intermediate gear is borne in a small fork built from the rear stay to the back fork, the back fork on that side being of D section, though round on the other side. The workmanship is of the highest quality, and the easy movement of this model is very interesting. It is very hard to find a bicycle of any sort to beat this in ease, quiet and smoothness, spinning clean and without load. A gear case is offered at $9 extra; a skeleton case is also offered at $2.

The device is the well-known Carroll spur gear, the same as used by Starbuck, the middle-distance racer, on the track not very long ago. At first sight, it might appear that sand and mud might create a disturbance by edging themselves into these small gears, but the makers maintain that a gear case is unnecessary, because the gears practically clean themselves, in consequence of each gear wheel running in direction opposite to that of its neighbor. In actual use upon muddy roads, through all sorts of weather, and under all conditions, it is claimed that the spur gears not only did not collect mud and dirt, but that they actually cleaned themselves, and while it is possible that a pebble or a piece of metal thrown in among the teeth might cause a breakage, it can only be said that in many hundred miles riding, the tests having been made under extremely unfavorable conditions, during rain, mud, storm and snow, no such difficulty was apparent. The tests developed unusual and unexpected qualities, and all the riders were fully convinced of its thorough practicability.