Without exagerating, one could say that the wheel was the most important technical invention of all time. All the more regrettable is, that apparently, it had to be re-invented several times! Indeed, in approx. 2000 BC the Egyptians probably didn't know, that the wheel was already known to the Sumerians in 3500 BC. It is possible however, that they simply never really knew what to do with it. Similar to the native inhabitants of America, who supposedly, had no knowledge of the wheel till into the 18th century.
Some say that the wheel was developed from a slice of a tree trunk. However, as you can see in the 1st picture, this is not at all suitable. Only then, when the wheel is made up of three parts (picture 2) and is given an axle, can it convert a sliding- into a rolling friction. This is why wheel bearings with rolling elements were later installed. However, first of all, wood remained the material, part of the time very nice spokes were produced, to maintain the same firmness and at the same time saving weight. Even as early as in the Roman times, iron material came into play. An iron band was spanned around the outside of the wheel and in the hub, together with some sort of lubricant it made the bearings more durable. Because of the bad roads the load was sprung against the axles using leather belts.
One thing is probably certain, if people were to be transported on wheels, the comfort would indeed, be a lot worse than if they were carried in a litter. It was more laborious to transport heavy loads on bad roads. Ships did the job much more efficiently and in fact, it was the railways, who, in the first half of the 19th century, for the first time, really brought the movement of heavy goods, rather than passengers, into being.
In 1846 the inflatable tyre was first invented by Robert William Thomson. Oddly enough, a railway engineer was having thoughts abut how the comfort, the rolling resistance and the noise development of carriage wheels could be improved. Presumably he had considered the application of his invention in railway coaches, they are the only ones, apart from those wheels with a thin rubber buffer-layer, where tyres were never used.
What made Thomsons invention, which was made up from a sort of flexible tube and an outer leather casing possible, was the development of vulcanisation in 1839 by Charles Goodyear. By adding special substances to the caoutchouc and by applying suitable heat, durable and very firm rubber could be manufactured. Unfortunately, humanity had still to wait for a while. After Thomson's death, the invention was simply forgotten about.
In the same century, the Irishman, John Boyd Dunlop, developed the pneumatic tyre. Actually it was only intended for his son's tricycle. A linen cloth was wound around an airtight rubber tube. If the tube needed to be repaired, the cloth had to be removed, layer for layer. The name of the first example was: 'Mummy-tyre'. All this is dated back to the year 1888, at the time when the safety-bicycle, with chain and pedals, was just taking over from the high-wheel-bicycles (Penny-Farthings).
Of course, the first two automobile builders, Daimler and Benz, still knew nothing about this invention. At this time in England, quickly following, the tyre-bead (William Bartlett), with the drop-center rim (Charles Welch), the valve (Charles Woods) and the replaceable inner tube (Édouard Michelin) were invented. The latter, together with his brother, was responsible for the first racing tests where a clear time-saving was achieved.
One problem, which would accompany the pneumatic tyre despite hundreds of patents, for more than fifty years, was the loss of air-pressure - the puncture - it wasn't only caused by the multitude of stray horshshoe nails lying around, but also through the strengthening linen material, the various layers chafed against each other. This was probably the only advantage that solid rubber tyres had as a buffer between the wheel and the road surface. It could be mounted using a great deal of effort at the repair shop preferred by motorists, the blacksmith.
In the beginning, solid rubber tyres had a superior load-carrying capacity, thus they remained in use on trucks for a long time, although the motor car tyre was driven with at least 5 bar pressure. Not only for this reason were they a real annoyance for the motorists. They had to be checked before almost each trip, which they often did not survive anyway. During a long motor race, changing the tyres up to 50 times was normal. This is why, when finally, in 1905 the removable wheel-rim appeared, it was considered a blessing.
At that time, there were of course, neither tyre-codes nor any suitable standardizations. Slightly damaged tyres could possibly be repaired on the spot, if the damage was greater, they had to be sent away, for an unknown period. New tyres were only purchased in exceptional cases. The price of tyres, despite the many other repairs and the short inspection intervals, were the highest cost factor when owning a motor car, sometimes the cost was even higher than that of the petrol.
To increase their endurance by up to five times what it was, from 1920 onwards, low pressure tyres were introduced. More than thirty years later one succeeded in developing the tubeless tyre through an additional sealing on the wheel-rim and in the inside of the tyre. These were simpler to mount and above all, under normal driving conditions, were also safer, because, e.g., the friction between inner-tube and the tyre was cancelled out. One disadvantage as far as mounting was concerned, was that, particularly later as radial tyres, there had to be a hump on each side, to prevent them from slipping into the drop-center when cornering or when a stronger pressure-loss took place.
At the same time, the first radial-tyre was invented by Michelin, indeed, it could only assert itself widely much later. In this case, the tread-surface was, through a stronger carcass, which sometimes had steel-wire threads worked into it, much more stable than the side-walls. This promised less rolling friction and more stability when cornering. The lower flexibility was compensated for by the vehicles spring suspension. This is how it then stayed, except that the tyres are now wider and their cross-section has become lower. 01/11
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