Page:Motors and motor-driving (1902).djvu/257

Rh enter into the situation which are virtually unknown in the case of the ordinary cycle. The motor-car not only surpasses in speed the greatest efforts of the cyclist, but also maintains a high momentum for protracted periods; hence overheating is one factor, not to mention others, which is present in the motor-tyre, but which in cycling is only known to the Alpine rider who 'coasts' for twenty miles or more with the brakes on all the time. The motor-car, too, must be driven through everything, including long patches of 'new metal,' and must take its grip on bad surfaces as well as good; the cyclist, on the other hand, can often pick his way, and, if not, can get down and push his mount, the tyres thus making a rolling contact only instead of sustaining the driving friction which does all the harm.

With all its drawbacks, however, the pneumatic tyre is almost indispensable for most types of motor-carriage. In speed, in comfort, in saving the mechanism from pronounced concussion, and in facility of steering, there is no question as to the superiority of the air chamber as compared with solid rubber. The curious fact, moreover, remains that in the very circumstances which emphasise the weak points of the pneumatic tyre the solid would be even worse. High speed and a heavy car form a combination which tests the pneumatic tyre severely, but the solid tyre in like circumstances can with difficulty be kept on the wheel at all. At high speed, again, the pneumatic tyre is particularly liable to puncture; but the very fact of the tremendous speed necessitates the rejection of the solid, because the comfort of the passengers, the conservation of the mechanism from jar, and the ease and safety of the steering become more than ever important.

It is a melancholy fact that our French neighbours have all along been even more ahead of this country in regard to the manufacture of motor-tyres than of motor-cars themselves. This circumstance for years pressed very hardly on the English amateur. In 1901, however, the Dunlop Company permitted the tyre which was most favourably known abroad, i.e. the