THAT CYCLOMETER. WHY IS IT UNRELIABLE?

Otago Witness, Issue 2362, 1 June 1899, Page 42

THAT CYCLOMETER.

WHY IS IT UNRELIABLE?

'Riders often, complain that their cyclometers are not accurate because the do not register the same as those of their riding (companions. As a general rule the cycloinetera register exactly the number of revolutions necessary in a wheel of given diameter to make a mile, and the differnce is due to the tyres or positions of the riders. By using two cyclometers dt once I tastepl Sifarly all the prominent makes for comparative acouracy. I found, says the writer, a conIributer to the Cycle, five that agreed exactly, one that was a mile slower than the five, and another that was three miles slow. These tests .were made by actual riding over all sorts of roads, and from one to 500 miles for each fcyclometor. There is nothing at all in the test of measuring the distance that a wheel travels in one revolution, finding the number of times that distance is contained in a mile, and then Epinning the wheel the required number of times.

The fallacy of this idea can be easily proven by measuring the distance covered by an unloaded wheel in one revolution and_ the distance covered by the same wheel with someone in the saddle. A difference of several inches will be noted.

The difference in sizes of tyres used on 28 inch wheels makes a very perceptible difference in mileage. The resiliency of a tyre also affects the reading of the cyclometer. A fast or resilient tyre will, by yielding to the small obstructions of the road, make a greater number of revolutions to a surveyed mile than a slower and less-yielding tyre. The airpressure also has something to do with it. If the tyre ib pumped very hard it will cover more ground to a cyclometer mile than when it is soft. Then the weight and position of the rider must be taken into account.

In coastfng the inclination of the hill shifls the centre of gravity forward, flattens out the front tyre and causes it to .gain on the surveyed mile. Tho opposite effect is, to some extent, produced in hill climbing. Owing to the numerous indentations made in a tyre on a rough road, less ground is covered to a mile by cyclometer than on a emooth road. The element of speed also enters ink the problem. The cyclometer of a man riding over a emooth and unobstructed road at a three minute gait will not register as much as when he goes over the same road at a ten mile pace. The loss is due to the fact that in rapid travelling the rider follows a more nearly straight line than when going at a moderate pacp.

Mr G-. H. Moore has sold to Mr Frank Jackton, Chrißtchurch. 3000 acres, or thereabouts, of the Deans block, forming part of the Glenftiark ebtntc, for £4 4b per acre, cash. It happened every night when father fell asleep, His little kid awoke to cough, and sneeze, and weep. Then father swore out loud and wished his ■ ." ■ kid was dead, . r And tore his new pyjamas jumping out of

bed; He damned — the cold linoleum stuck to his feet- like glue, As in his arms the child was howling all he

knew. But mother found a charm to make their rest The kid now thrives and sleeps on Woods's ?«onemizit Caret,