MOTORS AND MOTORING

Dominion, Volume 11, Issue 139, 1 March 1918, Page 11

MOTORS AND MOTORING

JBt Cmitoh.]

fiaro nf Tuhos. 'J ho fin-uL niiijnril.v nt' inotovisls could | Sii\u iiKiiH'.v by a lietlor innli-'i'staiidiin; ! mill liolk-i , - trwtnnMil .uf ihnir imior ! tiitifis. Jk'Ciiusi , tiil)i's> conio j p.n.'kcil in si j rsirdljoiird Imx niosl. poojilo MippilSl , I.lljs is il H<H><\ Wiiy'td prCliflTl! thoiii n'lii'ii wirriiid ill n cur; but th(! niiitiniied clmling cniisod by llip. motion of tho (.'iir will sooiHT (ir-lnti-.r result in injury. Tuhos should bu carricv:! in proper bugs.. Anolhi'r point is usiii|; tho riyiit size, of tube for (he cii.su. If too large a tiibo is inscitcd if wrinkles, aiul the tub?, clwl'es or splits :it tliose points; whik; if tho tube, is too sniiill it is constantly and. unduly stretched, which is not conducive, to long lift , . Tubes, arc so pliable, that, these points' arc apt, to be overlooked b.V ihp.ir users. As ciisesi by different makers may differ in. their interior dimonsioiis, although nominally of tho game size, it is best to iiso ijiner tubes supplied' by thn same makers as tho case. .'.... A Praptico Bari for Tyres. , Accordiug to'the head of. a big manu-f.'ic-fcuring .concorn in America, Inking turns and corners at unrensoniible. speed is one of the , worst ways a driver tan' l trout tyres—this for the reason thafj when corners are taken at excessive , speod si. terrific side. . strain is thrown on the thin walls .of tho two tyres on the outside of tlie turn, which tears and pulls the fabric at. its weakest point. "Recently," the manufacturer added, "we had a prominent professor,, who.is bead of the, department of engineering in olio of.tho leading universities, make.a series of tests for tho company, to ascertain the exact strain in pounds which is exerted on tho tyre side walls when the oar lakes n curve-at various speeds. Ho finds that with, a car weighing 2500 pounds, taking a curve of fifty feet radius at four miles- nn liour, no noticeable strain is exerted upon any-of the tyres, as the centrifugal tendency of tho motion is at its lowest ebb or is lost or absorbed owing to the slow speed of the car. However, if the car takes the same curve a.% twenty miles an hour, iiot.only is most of the actual weight, of, the 2500-pound car-thrown upon the two outer tyres, but an : additional side tfirust of about 1330 poijnds is created, or 665 pounds upon. , c.idli tyre. This means that ah. extra uiipalled-for force of nearly 700 pounds is' pulling, jerking, straining and. tearing the thin walls, while,-at tliesaiiiA time, practically half the weight-of the entire car is tiirow.n on each tyre. A number of interesting conclusions liafo been drawn as a result of these tests. For instanco, it is. found 1 that Wio heavier the car the greater is- tho 'strain, and the higher the. speed or momentum of the. car; the - greater the . strain also. The wider'or more, gradual the curve :ho less strain ;is thrown •.iipon the Outer tyres. If it were, possible for n 2500-pound car to take a- curve of fifty feet radius at fifty miles an hour without skidding or turning over, the centrifugal force would create, a side tbiust upon'.the tyres of 831.2 pounds, in addition to the weight of tho car. In other words, the side thrust would lie over three times the car's entire weight: Going at) twenty-five railos an hour the side thrust would be about 2035 pounds." Dearer Tyres. There is no doubt aiiotorists now get better results from 'their tyros than they did a few years back. Thero we not nearly so many cases of burstcovers or failure of fabric experienced, whilst the rubber wearing treads appear to withstand road friction better, and not to cut so readily as they did n few seasons back. With the improvements in manufacture find the increasing supplies of' raw materials the cost of tyres, when the war br.okc loose, had reached a price that enabled the average motorist to run a mediumpowerecj car without undue cost of upkeep for tyres, but since. 1911 the prices of raw materials and cost of manufacture hn-vo gradually been ascending, followed naturally by a'l incioased price to motorists. It is not tlie rubber that is gradually forcing up the price of motor covers, but the fabric of which tho casings of covers are made. During the last few months cotton lias jumped nearly 200 per cent, in America, and then is nearly unobtainable. Thoso manufacturers who were fortunate to hold good supplies of tyre fabric have been able to market their cover at but slight advance, but as the old stocks are depleted, and the new high-priced cotton comes into use, the prices of tyres in the Commonwealth and Now Zealand must bo based on the dearer materials incorporated, plus heavy freights. This means that motor tyro prices must advance in this part of 'tho world, just as they will in America and England. Here and There. Sparking plugs that- have become wet, as from rain, aro an annoyance, to say tiie least, yet this trouble sometimes occurs,with the motor-cycle owing to the (-(xposed position of the plugs. A pliin that answers well—especially so wluiro tho plugs are set upright in the cylinder—is to protect the plug with a dome of 'brass The half of a brass ball I 'from il decorative cur-tain-polo end (tan be,', bought at any house funnelling stoi't.c, and is well ridapted for the purpose. The spun hemispheres are! hold together simply by friction, and are easily separated. Simply drill a small liolo for the terminal screw, and scriiw the shell in place with the, tormina] nut. The device, aside from keeping the plug free from the least trace acts us a beat radiator, considerably reducing the working temperature of tho piug, and adding to its life as a matter of course. . ■ . '

Considerable, interest is being taken in English motor-cycle Irade circles over a" new motor-cycle design for which patents have been applied for. The. machine is said to coiitiiin many interesting features. The fxeme is of an entirely new pattern, and lilie rider, instead of being seated in th« ordinary way upon the saddle, lists at his disposal a very comfortable mid completely sprung seat. The is a four-cylinder one, and a combination friction and bevel gear drive, is cmployed, for transmission purposes. [t is proposed to fit either wheel or handle-bar steering at option, and. indued, the machine as a whole cmnes rear to being the ideal car on two wheels. Lighting-up time:—To-day, Gi.36 p.m. Next Friday, 6:25 p.m.