MOTOR AND CYCLE.

Taranaki Daily News, 27 November 1920, Page 9 (Supplement)

MOTOR AND CYCLE.

INEWS AND NOTES. 13th. Nov. 1020. _ Tyre manufacturers in Great Britain and Europe have for many years specialised in what are known as "beadededge"' covers, and what the Americans call the "clincher" tyre fur motor-cars, a type which has reached ft high decree of perfection. Since the close of the war, or thereabouts, much attention has been directed to the popular American "straight-edged" or "straight-sided"' tyre cover, which is used almost exclusively in the United States and other countries in the New World; and the presence of so many American automobiles in flveat Britain lilted with these covers has caused the tyre manufacturers in England, and in Europe generally, to seriously consider which will eventually triumph, the straight-edge or beaded-edge pattern. The matter has been brought to a head the sooner because of the extreme difficulties experienced by European motor manufacturers in regard to production since the Armistice, an opportunity of which the Americans fully availed themselves, as shown bv the laYge number of Yankee cars imported fit ted with straight-edged tyres. Commenting on the subject, tiie ''Autocar'' (Eng.) declares that, sooner or later, a definite decision must be reached as to whether the bcadod-edgc or the straight-side type of tyre shall definitely be established as the standard motor tyre of the world, for the production of cars in America has nowreached such huge proportions, and are to be found in almost all countries, that it ;s impossible for this question to he shelved. Practically, the straight-side cover'is a reversion to the "Welch palent, or wired-on bicycle tyre, hut as It obviously cannot be manipulated (forced over" the edge of the rim) as in the case of the cycle tyre, (lie rim itself is divided circumferentially, the outer edge is demountable, removable and when in position is secured by an approved device. The removal of (lie outer side of (he rim facilitates the cliaiiiiiiirv ( ,f a punctured tube or damaged cover, v ,ich la Iter enn be fitted or replaced without the use of tyre levers, and also if used when deflated less damage results than with the headed edge tyre. The Use of tyre levers, as in the case of the clincher tyre, is repugnant to main csnuetnllv wilh a new SMHI still" cpver, when the work en- * / » considerable; and sometimes the operation has ( n be repeated i ) 0. '■c.uso the inner tube was nipped in the original attempt. But the difficulty usin<r 11K* loveis i* much exajjporaUuh given n little practice with levers Ion" eiioii.nl, and of suitable shape, the jot. of fitting even a stiff cover is liy no means formidable. The elimination of tyre levers, however, is desirable. Another advantage claimed for the straight-edge cover is thai no security holts are necessary; here again, while it were better to bv? no security bo.ts. the manipulation of these part-- is really not a dillicuh job. It also is claimed that greater air pressure can lie applied with the American tyres, but if sufficient inflation is obtainable with the clincher type, and that is not quest ioned, the point is not worth considering. (n any ;m<e the tube bed; much better with the bended C(<vpr. Now as the type? of tyres under notice are not interchangeable on the rims, it is evident that the rim will be 'he deciding factor: hut if it were conceded that a change in Eurone to American practice is desirable, it' cannot he etiected in a day, or in a year for thai matter. Apart from the fact that there nro hundreds of thousands of ears in use fitted with beaded-edged tvres. and would not, or could not all be refitted with nms to take the straight-sided covers, tyre manufacturers in Europe an enormous number of verv expensive moulds and machines suitable only for the production of the beadededge tyre, to scrap all of which would cause expense so <r r eaf that the money expended' would have to lie recovered from the purchasers of the new l»nn of tyre. Writing to (he Autocar, a correspondent Tleclares that only two advantages stand out as being improvemcnts to be claimed for the straightedge tyre, ease of manipulation, and aosenee of rim damage if used in a deflated condition. He then pertinently asks, -'-What benefit is there to be derived from the straight-sided wired-on tyre which necessitates the use of a flanged rim, that cannot he obtained from the clin-cher-type tyre if used with the sum" flanged nm? Surely that is the whole question." He then describes the difficulties experienced with the American type of tvre. first pointing out that some !>0 per cent, of the cars used in tha Lnited States arc fitted with collap?ih!e (contractable) rims, which w!:en reduced in circumference, enables the inexpansible straight-edged wiredon cover to lie forced over, much in the same way as the clincher type. These I'lms require a special fool with which hey arc tightened or released, and so long as (hey are new and clean the operation is not very difficult, but when choked with mud and rusted up it is a very <1 liferent matter. And the same applies to a very great extent wilh the flanged rim; for unless the surface of the rim is clean and smooth there is trouble In fitting a new cover. If there is a change to be made, and it. has not vet been proved to he necessary, or even desirable pi- expedient, theft' nuibt 1)0 1 greater advantages shown for the Sti-aieht-edgc type of tyre together with (he elimination ofjfs drawbacks, while the transition must extend over a period of years, for there will likely bo millions of covers required for the'hundreds of thousands of cars in use lilted flilh wheels which take clincher .-overs "Illy, and which cannot. p,»,(.>-v.ill no< '-, ''hanged (o acconnuoi'.ale the stiaight-edged wifed-an Ann-rU-iiii i<pe of tyre. -Although |here exists m -.lmo-i all countries legislation prohibiti i- the use of dazzling hcadliL'hi - ~n mot or (he reason why it ; is not enforced is because there rc-i II y is no means available to cionpjy with 1111law. In a perfiniflory sort of w:iv, mot nri-'N observe the regulation bv picvemiuy: the uppcrino.-l rays of the headlight beino- projected : more than -( II ct above road level. in providing a light that would an.iYver the requirements nf ihc motorist, that would comply with the law, but would not dazzle other road users a nice problem had. to ho solved. fii a napl'r prepared by Mr. J. Oi-e.emc Raillie, .A.M.T.R.E., of Melbourne, results of a, number of interesting experiments are' jjiveu. Willi the projector used a fan •-dinned beam of light was thrown so thai the roadway was brilliantly illn'iijr.ated up to 1-i') yds, distance, with breadth of M > - a*ds. and not higher ;> :ft. »l,ow> Although - icn a ' result

might appear perfect, such was not the case, as the motorist could see only portions of the legs of persons or horses and parts of wheel*. The fact is that, tlio human eye is accustomed to see complete objects, and to see them in relation to surrounding objects, that is, ill perspective. Pedestrians then were caused to walk straight ahead from the projector, and it was noted that at 65 yards visibility, that is instant appreciation, ceased; and although the observer behind l.lie projector' could sea these people at that distance with difficulty, pedestrians with their back to the light, could see a further distance of 100 yards and recognise objects distinctly.' This proved that the reflected liglit from the brilliant'v illuminated road surface was actually producing a. glare sufl'eient to interfere with the resolving power of the eye of the observer. Provided the pedestrians kept their eyes above the height of illumination there was no interference with their vision. What has to he ascertained is that intensity of light which can be projected into the eyes of a person without interference with that person's vision on the one hand, and on the other, which permits of an observer placed behind the projector to see that person plainly clearly up to, say, 80 yards from the projector. But experiment revealed that the vision of all persons is not alike; what was glare to one, was not, to another. Some had astigmatism, and others were, normal, it was decided to introduce means to diffuse the projected light because it was recently established that for accurate definition at a distance far better results c.ould. lie obtained by a much reduced intensity of lighting, provided if be diffused, than bv direct lighting of great intensity, the relative intensity being as one is to four; and the nature of the road lighting achieved by this innovation was a vast improvement on that produced by direct lighting. although the unit intensity of lighting was reduced to one quarter. It is considered that (he ideal headlight must (I) bo incapable of producing a beam intensity greater than tiiat, which the eye can view without interference to vision; {•>) project a uniformly * distributed diffused beam of light which illuminates the total breadth of the average roadway nnd the whole ol the .objects met witli; (3) be made astigmatic as far as its optics are concerned, because this is the only means known whereby light can be projected efficiently as a strip or bar in cross section. The dimming device? at present permitted are considered unsatisfactory, because in the event of a travelling car striking a bump the light is thrown upwards, momentarily dazzling pers'ons looking at it; and unsatisfactory from a motor ist's point of view because there is inadeoiinte lighting of objects on the londway. Dimmers also are at times wrongly applied, because if the source of lk'ht j? placed exactly at the focal point, the efiect is to reduce the volume of liglit by one half.