Views of Motor Wagon Carriers about Solid Rubber Tires for Five-tonners.
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By The Editor.
Lancashire owners have been taking keen interest the question of solid-rubber tires for five-ton wagons : their minds are well settled in regard to the necessity for these resilient treads upon smaller vehicles, but there is not yet unanimity about fivetonners. The balance of opinion is undoubtedly, at the moment, against rubber for use upon steam wagons that carry more than 34 tons, although nobody advocates the use of big petrol lorries with steel tires. The feeling clearly is that rubber will of necessity come into more-general use. The writer, during a round of visits that were paid last week, took the opportunity to obtain views and experiences which relate to the past two years. A digest of these, now presented, cannot fail to serve as a guide to many carriers and other owners who are still hesitating between petrol and steam, or between rubber and steel, for the tires of their choice. Comment of our own will also be apparent. The references to petrol and steam are incidental.
Running to Time.
An insufficiently-appreciated factor is the greater assuredness of running to time which the employment of solid-rubber tires confers. Steel tires, under working conditions which are common and recurring throughout Lancashire, Yorkshire and other counties w.ithin road-traffic distance of Manchester, perpetuate risks of delay that may—and frequently docause material loss. They are unreliable for the following reasons amongst others: in dry weather, skidding occurs on dry and sun-polished granite setts, and on sonic forms of macadam ; in winter, the steel-tired vehicle is useless (and sometimes positively dangerous) on snow or on ice-bound roads ; in any season of the year, when rain or atmospheric humidity occasions the formation and persistence of a skin of slimy mud, both skidding and sideslip are troublesome. Uncertainties are thus, oftentimes, inseparable from any service which is concluded upon steel-tired wheels, whereas the rubber-tired wheel is proof against all but I he last. There are, however, comparatively-few cases in which skidding and sideslip occur on "grease" when rubber is used. A rubber-tired lorry is practically never late on its round by reason of lost time due to want of adhesion—to inability to " get a bite on the surface. '
Running on Snow.
It, is old knowledge. that the steam wagon on steel I ires has to stay where it is when snow begins to fall. The owner who finds his vehicle or vehicles in the depot at such a time is lucky. A rubber-tired lorry, on the other hand, can safely run on or through from s in. to 12 in. of snow, no matter whether the power he steam or petrol. Short drifts can also be successfully " charged " and surmounted. in cold weather, when a steam lorry is brought to a standstill because of snow, some damage usually occurs through the burst jog of pipes or joints, as it is not. always simple to get water out of bends. The petrol lorry is not subject to either drawback. Rubber tires mean that either power can get home, every night, as a rule.
Costs Per Mile.
Two years ago, it cost 5d. per mile run for solidrubber tires on a five-ton steam wagon. This cost has now fallen to 3d. By 1914, it is hoped, the flood of new yield from Eastern plantations will see the cost down to 1.5d. There is "nothing in it" between the present-day cost of the tires fer a petrol or a steam
five-tonner. If anything, for gear-driven petrol lorries with a certain amount of extra unsprung weight, the cost is, perhaps, 0.25d. per mile higher than tor a chain-driven steamer. This cost, of course, is not all to be regarded as extra outgo, compared with running on steel tires—which cost only, say, one-tenth of a penny a mile themselves. The petrol chassis needs them constructionally ; relative costs of repairs are lessened by their use. An extra cost, now, of something like 2.5d. per mile is net. How is that recouped I
When Rubber Pays, and Why.
Rubber pays back more than it costs under many Lancashire running and service conditions. The higher speeds allowed are found to produce increased earnings, A concrete instance is the Manchester-Oldham-Blackburn-Manchester round trip of three stages. This totals 60 miles. It can regularly be done in the working day by a rubber-tired petrol wagon. No vehicle on steel tires could do it. Apart from the valuable factor of keeping time on rubber tires, their use is accompanied by fewer road accidents. Again, the drivers suffer less from fatigue, and are therefore better at their work.
Numerous owners who have tried both find that vehicles with rubber tires seldom get " out of step" with the order of the work they are put to do. One example adduced concerns loads of cloth from Darwen to Manchester, and yarn in skips as back loads. Wagons on steel tires, each hauling a trailer, can barely do the double trip : they have to pick up the yarn in Manchester, and they very often fail to get. rid of their deliveries of cloth in time. Sometimes they Ailt have cloth undelivered when the warehouses close (5.30 p.m.), which means staying in Manchester overnight and getting "right out" with their programme, so that a day's revenue has to be sacrificed. If the cloth be delivered by 5.30 p.m. and they miss the back load of yarn, they can, of course, travel back light, and lose only one paying trip, in order to be ready to load up cloth at the mill the next morning. When rubber is fitted, the wagons (without trailers> save enough time on the journey to Manchester to insure their getting rid of the load of cloth every day, are able to collect the skips of yarn at Ashton. Oldham, or elsewhere, instead of in Manchester, and do not get out of time in their running. The extra revenue pays for the tires, and the earnings are certain instead of precarious. The least delay does not throw the rubber-tired vehicle out: it can bear delays at the warehouses, because it is quicker on the road.
Rubber and Roads : Excessive Speeds.
The inter-relation between rubber tires and roads, calls for mention, particularly with reference to future improvements. It is commonly thought. that the nature of the surfacing materials is the worst; factor in causing undue damage, and gritty or loose macadam crusts are disliked by owners in consequence. It is too often forgotten that fast driving over firm but irregular surfaces gives rise to impacts which occasion blows to be received locally by the tires to intensities in excess of their resistance to crushing. The structural cohesion is broken down. and the tires deteriorate. Much unsprung weight hastens the process, and some tire makers are talkiny, of taking that point into account when quoting mileage contracts. It. is of interest to the industry and themovement, that the general improvement of roadshould progress. Rubber tires will then cost less.