text: বাইসাইকেল মানুষ পরিবহণের জন্য ব্যবহৃত যানবহন। বাইসাইকেলের রয়েছে দুইটি চাকা এবং গুরুত্বপূর্ণ হলো এটা চালানোর জন্য ভারসম্য প্রয়োজন। ১৯ শতকের গোড়ার দিকে সাইকেল চালনার রচনা হয়। এই পরিবহন তৈরির প্রথম মাধ্যম ছিল দুইটি চাকা পরপর সাজানো এবং এভাবে ১৮১৭ সালে জার্মান ড্রাইসিন সাইকেলের আদিরূপ পাওয়া যায়। বাইসাইকেল শব্দটি ১৮৬০ এর দশকে ফ্রান্সে সৃষ্টি  হয় এবং "সাধারণ বাইসাইকেল"কে বোঝানোর জন্য ব্যবহৃত বর্ণনামূলক শিরোনাম হল "পেনি ফরথিং", যা ১৯-শতাব্দীর শব্দ।
  
  ১৮৮৮ সালে আধুনিক সাইকেলের সূচনা হয়।ফ্রান্সের পিয়ের মিশো এবং যুক্তরাষ্ট্রের পিয়ের লালেমেন্ট- এই দু’জন প্রথম প্যাডেল চালিত সাইকেল আবিষ্কার করেন। তবে দু’জনের কে আসল উদ্ভাবক তা কিন্তু আজও সঠিকভাবে জানা যায়নি। 
  যদিও ১৮৬৬ সালের ২০ নভেম্বর পিয়ের লালেমেন্ট সাইকেল উদ্ভাবনের জন্য তাঁর দেশে স্বীকৃতি লাভ করেন। সেই হিসেবেই আধুনিক বাইসাইকেলের আবিষ্কারের সময় ধরা হচ্ছে।
  
  বর্তমানে ঘনবসতিপূর্ণ এলাকায় সাইকেলের জনপ্রিয়তা বেশি।আমাদের দেশেও দিন দিন সাইকেলের জনপ্রিয়তা বেড়ে চলেছে।
  
  প্রারম্ভিক যাচাইবিহীন বাইসাইকেল 
  বাইসাইকেলের আবিষ্কার বেশ প্রাথমিক , তবে তা যাচাই করা হয়নি বলে দাবি রয়েছে। ১৫০০ খ্রিস্টাব্দের কাছাকাছি লিওনার্দো দা ভিঞ্চি্র এক ছাত্র জিয়ান গিয়াকোমো ক্যাপ্রোটি বাইসাইকেলের চিত্র অঙ্কন করেন, তবে এটি নিয়ে ১৯৯৮ সালে হান্স-এরহার্ড লেসিং বলেন এটি একটি উদ্দেশ্যমূলক জালিয়াতি । যাইহোক, বাইসাইকেল অঙ্কনের সত্য ঘটনা অধ্যাপক অগস্টো মেরিনোনির অনুসারীরা এখনও দৃঢ়রূপে রক্ষণাবেক্ষণ করেছেন। অগস্টো মেরিনোনি ছিলেন একজন অভিধান সংকলক এবং ভাষাবিজ্ঞানী যিনি রোমের কমিশনে ভিনসিয়ানার লিওনার্দোর কোডেক্স আটলান্টিকাসের নকলকরণের প্রতি আগ্রহী ছিলেন।
  
  পরে, এবং সমান যাচাইবিহীন বিতর্ক করা হয়েছে যে, ১৭৯২ সালে সুনিশ্চিত "কমট ডি সিভরাক" ক্যলেরিফেরি বিকাশ করেছে । এই ক্যলেরিফেরি ফ্রান্সের প্যালাইস-রয়্যালে প্রদর্শন করা হয়েছে। ক্যলেরিফেরিতে সম্ভবত দুটি চাকা যুক্ত ছিল এবং অনমনীয় কাঠের শরীর ও হাত দিয়ে পরিচালনার জন্য কিছু ছিলনা । গতপথ নিয়ন্ত্রণ সীমাবদ্ধ ছিল এবং হেলান দিয়ে যে গতিপথ নিয়ন্ত্রণযোগ্য।  একজন চালক বলেছিল দুই পাশে দুই পা ফাঁক করে বসা এই যন্ত্র বারবার ধাক্কা দেওয়া অতিরিক্ত চরণযুঘল। এখন মনে করা হয় যে, দুই চাকার ক্যলেরিফেরি কখনোই ছিল না (যদিও সেখানে চাকা ছিল) এবং এই বিষয়ে ১৯৮১ সালে প্রখ্যাত ফরাসী সাংবাদিক লুই বাউড্রি ডি সুনিয়ার অপব্যাখ্যা দিয়ে ছিল।
  
  ১৯ শতক
  
  ১৮১৭ থেকে ১৮১৮: ড্রাইসিন এবং তিন চাকার সাইকেল  
  
  ব্যবহারিকভাবে ব্যবহৃত বাইসাইকেলের প্রথম যাচাইযোগ্য দাবী জার্মান ব্যারন কার্ল ভন ড্রাইস করেছিলেন। তিনি জার্মানির গ্র্যান্ড ডিউকের বাডেনের একজন সরকারী কর্মচারী ছিলেন। ১৮১৭ সালে ড্রিস তার লাউফমাসচিন (জার্মান "চলমান মেশিন") আবিষ্কার করেছিলেন। যাকে প্রেস দ্বারা ইংরেজিতে ড্রেইসিন  বা ফ্রেঞ্চে ড্রেসিয়েন বলে ডাকা হয়। কার্ল ভন ড্রইস ১৮১৮ সালে এই নকশাকে পেটেন্ট করেন, এটি ছিল প্রথম বাণিজ্যিকভাবে সফল দুই চাকা, চালমান, মানব চালিত যন্ত্র, যাকে সাধারণত একটি বেগ বলা হয এবং ডাকনাম শখের ঘোড়া বা ড্যান্ডি ঘোড়া বলা হয়। প্রাথমিকভাবে এটি জার্মানি এবং ফ্রান্সে তৈরি করা হয়েছিল।
  
  হান্স-এরহার্ড লেসিং (ড্রইজের চরিতকার) থেকে পরিস্থিতিগত প্রমাণ পাওয়া গেছে যে, ড্রইসের আগ্রহের জন্য ঘোড়ার বিকল্প অনুসন্ধান ছিল ব্যপক এবং ১৮১৬ সালে গ্রীষ্মদের দিন ছাড়াই (১৮১৫ সালে তাম্বোরার আগ্নেয়গিরির অগ্নুৎপাতের পরে) বিফল ফসলের কারণে ঘোড়ার মৃত্যুর ঘটনা ঘটে।
  
  ১৮১৭ সালের ১২ জুন ম্যানহিম নামক এক ব্যক্তি প্রথম সাইকেল চালনা করেন এবং তিনি জ্ঞাপিত করেন যে, তিনি এক ঘণ্টারও কম সময়ে ১৩ কিলোমিটার (আট মাইল) যাত্রা করেছিলেন। প্রায় সম্পূর্ণ কাঠের তৈরি ড্রাইসিনের ওজন ২২ কেজি (৪৮ পাউন্ড),একটি স্ব-কেন্দ্রীকরণ কাস্টার প্রভাব জন্য বাইসাইকেলের চাকায় ছিল বিয়ারিংয়ের মধ্যে পিতলের গুল্ম , লোহার শড চাকা, একটি পিছন চাকার ব্রেক এবং ১৫২ মি.মি. (৬ ইঞ্চি) সামনের চাকার লেজ।  এই নকশাটি ভারসাম্য বজায় রাখার কারণে দু:সাহসী যান্ত্রিক চিন্তাধারার লোকেরা এটিকে স্বাগত জানিয়েছিলেন এবং মূলত পশ্চিম ইউরোপ এবং উত্তর আমেরিকায় কয়েক হাজার অনুলিপি তৈরি এবং ব্যবহার করা হয়েছিল। আংশিক ক্রমবর্ধমান দুর্ঘটনার কারণে, কিছু শহর কর্তৃপক্ষ এর ব্যবহার নিষিদ্ধ করতে শুরু করলে এর জনপ্রিয়তা দ্রুত ম্লান হয়ে যায়। তবে, ১৮৬৬ সালে প্যারিসে বিন চুন নামে একজন চীনা দর্শনার্থী পা-ধাক্কা দেওয়া বাইসাইকেল চালাতে পারতেন।
  
  ধারণাটি বেশ কয়েকটি ব্রিটিশ কার্টরাইট দিয়েছিলেন; সর্বাধিক উল্লেখযোগ্য ছিলেন লন্ডনের ডেনিস জনসন, তিনি ১৮১৮ সালের শেষদিকে ঘোষণা করেছিলেন যে তিনি একটি উন্নত সাইকেলের মডেল বিক্রি করবেন। New names were introduced when Johnson patented his machine “pedestrian curricle” or “velocipede,” but the public preferred nicknames like “hobby-horse,” after the children's toy or, worse still, “dandyhorse,” after the foppish men who often rode them.  Johnson's machine was an improvement on Drais's, being notably more elegant: his wooden frame had a serpentine shape instead of Drais's straight one, allowing the use of larger wheels without raising the rider's seat, but was still the same design.
  
  During the summer of 1819, the "hobby-horse", thanks in part to Johnson's marketing skills and better patent protection, became the craze and fashion in London society. The dandies, the Corinthians of the Regency, adopted it, and therefore the poet John Keats referred to it as "the nothing" of the day. Riders wore out their boots surprisingly rapidly, and the fashion ended within the year, after riders on pavements (sidewalks) were fined two pounds.
  
  Nevertheless, Drais's velocipede provided the basis for further developments: in fact, it was a draisine which inspired a French metalworker around 1863 to add rotary cranks and pedals to the front-wheel hub, to create the first pedal-operated "bicycle" as we today understand the word.
  
  ১৮২০ থেকে ১৮৫০ এর দশক: ৩ এবং ৪-চাকার সাইকেলের যুগ 
  
  যদিও প্রযুক্তিগতভাবে দ্বি-চাকার ("সাইকেল") ইতিহাসের অংশ নয়। তবে ১৮২০-এর ১৮৫০ এর মধ্যবর্তী দশকগুলিতে মানব চালিত পরিবহন সম্পর্কিত প্রায়শই বিকাশের সাথে একই রকম প্রযুক্তি ব্যবহার করে এরকম অনেক বিকাশ প্রত্যক্ষভাবে বিকাশ করেছিল, এমনকি যদি একটি কার্যকর দুই চাকার নকশার ধারণা চালকের ভারসাম্য বজায় রাখার প্রয়োজনে বাদ দেওয়া হয়েছিল। These new machines had three wheels (tricycles) or four (quadracycles) and came in a very wide variety of designs, using pedals, treadles, and hand-cranks, but these designs often suffered from high weight and high rolling resistance. However, Willard Sawyer in Dover successfully manufactured a range of treadle-operated 4-wheel vehicles and exported them worldwide in the 1850s.
  
  1830s: the reported Scottish inventions
  The first mechanically propelled two-wheel vehicle is believed by some to have been built by Kirkpatrick Macmillan, a Scottish blacksmith, in 1839. A nephew later claimed that his uncle developed a rear-wheel drive design using mid-mounted treadles connected by rods to a rear crank, similar to the transmission of a steam locomotive. Proponents associate him with the first recorded instance of a bicycling traffic offence, when a Glasgow newspaper reported in 1842 an accident in which an anonymous "gentleman from Dumfries-shire... bestride a velocipede... of ingenious design"  knocked over a pedestrian in the Gorbals and was fined five British shillings. However, the evidence connecting this with Macmillan is weak, since it is unlikely that the artisan Macmillan would have been termed a gentleman, nor is the report clear on how many wheels the vehicle had.  The evidence is unclear, and may have been faked by his son.
  
  A similar machine was said to have been produced by Gavin Dalzell of Lesmahagow, circa 1845.  There is no record of Dalzell ever having laid claim to inventing the machine.  It is believed that he copied the idea having recognised the potential to help him with his local drapery business and there is some evidence that he used the contraption to take his wares into the rural community around his home.  A replica still exists today in the Glasgow Museum of Transport.  The exhibit holds the honour of being the oldest bike in existence today. The first documented producer of rod-driven two-wheelers, treadle bicycles, was Thomas McCall, of Kilmarnock in 1869. The design was inspired by the French front-crank velocipede of the Lallement/Michaux type.
  
  1853 and the invention of the first modern bicycle "Tretkurbelfahrrad" by Philipp Moritz Fischer 
  Once again Germany was the center of innovation, when Philipp Moritz Fischer, who had used the Draisine since he was 9 years old for going to school, invented the very first bicycle with pedals. in 1853. After years of living all over Europe, he left London to go back to his native town of Schweinfurt , Bavaria, when his first son died at a young age. He built the very first modern bicycle with pedals in 1853. The Tretkurbelfahrrad from 1853 is still sustained and is on public display in the municipality museum in Schweinfurt.
  
  1860s and the Michaux "Velocipede," aka "Boneshaker" 
  The first widespread and commercially successful design was French. An example is at the Museum of Science and Technology, Ottawa. Initially developed around 1863, it sparked a fashionable craze briefly during 1868–70. Its design was simpler than the Macmillan bicycle; it used rotary cranks and pedals mounted to the front wheel hub. Pedaling made it easier for riders to propel the machine at speed, but the rotational speed limitation of this design created stability and comfort concerns which would lead to the large front wheel of the "penny farthing". It was difficult to pedal the wheel that was used for steering. The use of metal frames reduced the weight and provided sleeker, more elegant designs, and also allowed mass-production.  Different braking mechanisms were used depending on the manufacturer. In England, the velocipede earned the name of "bone-shaker" because of its rigid frame and iron-banded wheels that resulted in a "bone-shaking experience for riders."
  
  The velocipede's renaissance began in Paris during the late 1860s. Its early history is complex and has been shrouded in some mystery, not least because of conflicting patent claims: all that has been stated for sure is that a French metalworker attached pedals to the front wheel; at present, the earliest year bicycle historians agree on is 1864. The identity of the person who attached cranks is still an open question at International Cycling History Conferences (ICHC). The claims of Ernest Michaux and of Pierre Lallement, and the lesser claims of rear-pedaling Alexandre Lefebvre, have their supporters within the ICHC community.
  
  Bicycle historian David V. Herlihy documents that Lallement claimed to have created the pedal bicycle in Paris in 1863. He had seen someone riding a draisine in 1862 then originally came up with the idea to add pedals to it. It is a fact that he filed the earliest and only patent for a pedal-driven bicycle, in the US in 1866. Lallement's patent drawing shows a machine which looks exactly like Johnson's draisine, but with the pedals and rotary cranks attached to the front wheel hub, and a thin piece of iron over the top of the frame to act as a spring supporting the seat, for a slightly more comfortable ride.
  
  By the early 1860s, the blacksmith Pierre Michaux, besides producing parts for the carriage trade, was producing "vélocipède à pédales" on a small scale. The wealthy Olivier brothers Aimé and René were students in Paris at this time, and these shrewd young entrepreneurs adopted the new machine. In 1865 they travelled from Paris to Avignon on a velocipede in only eight days. They recognized the potential profitability of producing and selling the new machine. Together with their friend Georges de la Bouglise, they formed a partnership with Pierre Michaux, Michaux et Cie ("Michaux and company"), in 1868, avoiding use of the Olivier family name and staying behind the scenes, lest the venture prove to be a failure. This was the first company which mass-produced bicycles, replacing the early wooden frame with one made of two pieces of cast iron bolted together—otherwise, the early Michaux machines look exactly like Lallement's patent drawing. Together with a mechanic named Gabert in his hometown of Lyon, Aimé Olivier created a diagonal single-piece frame made of wrought iron which was much stronger, and as the first bicycle craze took hold, many other blacksmiths began forming companies to make bicycles using the new design. Velocipedes were expensive, and when customers soon began to complain about the Michaux serpentine cast-iron frames breaking, the Oliviers realized by 1868 that they needed to replace that design with the diagonal one which their competitors were already using, and the Michaux company continued to dominate the industry in its first years.
  
  On the new macadam paved boulevards of Paris it was easy riding, although initially still using what was essentially horse coach technology. It was still called "velocipede" in France, but in the United States, the machine was commonly called the "bone-shaker". Later improvements included solid rubber tires and ball bearings. Lallement had left Paris in July 1865, crossed the Atlantic, settled in Connecticut and patented the velocipede, and the number of associated inventions and patents soared in the US. The popularity of the machine grew on both sides of the Atlantic and by 1868–69 the velocipede craze was strong in rural areas as well.  Even in a relatively small city such as Halifax, Nova Scotia, Canada, there were five velocipede rinks, and riding schools began opening in many major urban centers.  Essentially, the velocipede was a stepping stone that created a market for bicycles that led to the development of more advanced and efficient machines.
  
  However, the Franco-Prussian war of 1870 destroyed the velocipede market in France, and the "bone-shaker" enjoyed only a brief period of popularity in the United States, which ended by 1870. There is debate among bicycle historians about why it failed in the United States, but one explanation is that American road surfaces were much worse than European ones, and riding the machine on these roads was simply too difficult. Certainly another factor was that Calvin Witty had purchased Lallement's patent, and his royalty demands soon crippled the industry. The UK was the only place where the bicycle never fell completely out of favour.
  
  1870s: the high-wheel bicycle
  
  The high-bicycle was the logical extension of the boneshaker, the front wheel enlarging to enable higher speeds (limited by the inside leg measurement of the rider), the rear wheel shrinking and the frame being made lighter. Frenchman Eugène Meyer is now regarded as the father of the high bicycle by the ICHC in place of James Starley. Meyer invented the wire-spoke tension wheel in 1869 and produced a classic high bicycle design until the 1880s.
  
  James Starley in Coventry added the tangent spokes and the mounting step to his famous bicycle named "Ariel." He is regarded as the father of the British cycling industry. Ball bearings, solid rubber tires and hollow-section steel frames became standard, reducing weight and making the ride much smoother. Depending on the rider's leg length, the front wheel could now have a diameter up to 60 in (1.5 m).
  
  This type of bicycle was retronymed the "ordinary" (since there was then no other kind) and was later nicknamed "penny-farthing" in England (a penny representing the front wheel, and a coin smaller in size and value, the farthing, representing the rear). They were fast, but unsafe. The rider was high up in the air and traveling at a great speed. If he hit a bad spot in the road he could easily be thrown over the front wheel and be seriously injured (two broken wrists were common, in attempts to break a fall) or even killed. "Taking a header" (also known as "coming a cropper"), was not at all uncommon.
  
  The rider's legs were often caught underneath the handlebars, so falling free of the machine was often not possible. The dangerous nature of these bicycles (as well as Victorian mores) made cycling the preserve of adventurous young men. The risk averse, such as elderly gentlemen, preferred the more stable tricycles or quadracycles. In addition, women's fashion of the day made the "ordinary" bicycle inaccessible. Queen Victoria owned Starley's "Royal Salvo" tricycle, though there is no evidence she actually rode it.
  
  Although French and English inventors modified the velocipede into the high-wheel bicycle, the French were still recovering from the Franco-Prussian war, so English entrepreneurs put the high-wheeler on the English market, and the machine became very popular there, Coventry, Oxford, Birmingham and Manchester being the centers of the English bicycle industry (and of the arms or sewing machine industries, which had the necessary metalworking and engineering skills for bicycle manufacturing, as in Paris and St. Etienne, and in New England). Soon bicycles found their way across the English Channel. By 1875, high-wheel bicycles were becoming popular in France, though ridership expanded slowly.
  
  In the United States, Bostonians such as Frank Weston started importing bicycles in 1877 and 1878, and Albert Augustus Pope started production of his "Columbia" high-wheelers in 1878, and gained control of nearly all applicable patents, starting with Lallement's 1866 patent. Pope lowered the royalty (licensing fee) previous patent owners charged, and took his competitors to court over the patents. The courts supported him, and competitors either paid royalties ($10 per bicycle), or he forced them out of business. There seems to have been no patent issue in France, where English bicycles still dominated the market. In 1880, G.W. Pressey invented the high-wheeler American Star Bicycle, whose smaller front wheel was designed to decrease the frequency of "headers". By 1884 high-wheelers and tricycles were relatively popular among a small group of upper-middle-class people in all three countries, the largest group being in England. Their use also spread to the rest of the world, chiefly because of the extent of the British Empire.
  
  Pope also introduced mechanization and mass production (later copied and adopted by Ford and General Motors), vertically integrated, (also later copied and adopted by Ford), advertised aggressively (as much as ten percent of all advertising in U.S. periodicals in 1898 was by bicycle makers), promoted the Good Roads Movement (which had the side benefit of acting as advertising, and of improving sales by providing more places to ride), and litigated on behalf of cyclists (It would, however, be Western Wheel Company of Chicago which would drastically reduce production costs by introducing stamping to the production process in place of machining, significantly reducing costs, and thus prices.) In addition, bicycle makers adopted the annual model change (later derided as planned obsolescence, and usually credited to General Motors), which proved very successful.
  
  Even so, bicycling remained the province of the urban well-to-do, and mainly men, until the 1890s, and was an example of conspicuous consumption.
  
  The safety bicycle: 1880s and 1890s
  
  The development of the safety bicycle was arguably the most important change in the history of the bicycle.  It shifted their use and public perception from being a dangerous toy for sporting young men to being an everyday transport tool for men and women of all ages.
  
  Aside from the obvious safety problems, the high-wheeler's direct front wheel drive limited its top speed. One attempt to solve both problems with a chain-driven front wheel was the dwarf bicycle, exemplified by the Kangaroo. Inventors also tried a rear wheel chain drive. Although Harry John Lawson invented a rear-chain-drive bicycle in 1879 with his "bicyclette", it still had a huge front wheel and a small rear wheel. Detractors called it "The Crocodile", and it failed in the market.
  
  John Kemp Starley, James's nephew, produced the first successful "safety bicycle" (again a retrospective name), the "Rover," in 1885, which he never patented. It featured a steerable front wheel that had significant caster, equally sized wheels and a chain drive to the rear wheel.
  
  Widely imitated, the safety bicycle completely replaced the high-wheeler in North America and Western Europe by 1890. Meanwhile, John Dunlop's reinvention of the pneumatic bicycle tire in 1888 had made for a much smoother ride on paved streets; the previous type were quite smooth-riding, when used on the dirt roads common at the time. As with the original velocipede, safety bicycles had been much less comfortable than high-wheelers precisely because of the smaller wheel size, and frames were often buttressed with complicated bicycle suspension spring assemblies. The pneumatic tire made all of these obsolete, and frame designers found a diamond pattern to be the strongest and most efficient design.
  
  On 10 October 1889, Isaac R Johnson, an African-American inventor, lodged his patent for a folding bicycle – the first with a recognisably modern diamond frame, the pattern still used in 21st-century bicycles.
  
  The chain drive improved comfort and speed, as the drive was transferred to the non-steering rear wheel and allowed for smooth, relaxed and injury free pedaling (earlier designs that required pedalling the steering front wheel were difficult to pedal while turning, due to the misalignment of rotational planes of leg and pedal). With easier pedaling, the rider more easily turned corners.
  
  The pneumatic tire and the diamond frame improved rider comfort but do not form a crucial design or safety feature. A hard rubber tire on a  bicycle is just as rideable but is bone jarring. The frame design allows for a lighter weight, and more simple construction and maintenance, hence lower price.
  
  Most likely the first electric bicycle was built in 1897 by Hosea W. Libbey.
  
  ২০ শতক
  
  The roadster
  
  The ladies' version of the roadster's design was very much in place by the 1890s. It had a step-through frame rather than the diamond frame of the gentlemen's model so that ladies, with their dresses and skirts, could easily mount and ride their bicycles, and commonly came with a skirt guard to prevent skirts and dresses becoming entangled in the rear wheel and spokes. As with the gents' roadster, the frame was of steel construction and the positioning of the frame and handlebars gave the rider a very upright riding position. Though they originally came with front spoon-brakes, technological advancements meant that later models were equipped with the much-improved coaster brakes or rod-actuated rim or drum-brakes.
  The Dutch cycle industry grew rapidly from the 1890s onwards. Since by then it was the British who had the strongest and best-developed market in bike design, Dutch framemakers either copied them or imported them from England. In 1895, 85 percent of all bikes bought in the Netherlands were from Britain; the vestiges of that influence can still be seen in the solid, gentlemanly shape of a traditional Dutch bike even now.
  
  Though the ladies' version of the roadster largely fell out of fashion in England and many other Western nations as the 20th century progressed, it remains popular in the Netherlands; this is why some people refer to bicycles of this design as Dutch bikes. In Dutch the name of these bicycles is Omafiets ("grandma's bike").
  
  Popularity in Europe, decline in US
  Cycling steadily became more important in Europe over the first half of the twentieth century, but it dropped off dramatically in the United States between 1900 and 1910. Automobiles became the preferred means of transportation. Over the 1920s, bicycles gradually became considered children's toys, and by 1940 most bicycles in the United States were made for children. In Europe cycling remained an adult activity, and bicycle racing, commuting, and "cyclotouring" were all popular activities. In addition, specialist bicycles for children appeared before 1916.
  
  From the early 20th century until after World War II, the roadster constituted most adult bicycles sold in the United Kingdom and in many parts of the British Empire. For many years after the advent of the motorcycle and automobile, they remained a primary means of adult transport. Major manufacturers in England were Raleigh and BSA, though Carlton, Phillips, Triumph, Rudge-Whitworth, Hercules, and Elswick Hopper also made them.
  
  Technical innovations
  Bicycles continued to evolve to suit the varied needs of riders. The derailleur developed in France between 1900 and 1910 among cyclotourists, and was improved over time. Only in the 1930s did European racing organizations allow racers to use gearing; until then they were forced to use a two-speed bicycle. The rear wheel had a sprocket on either side of the hub. To change gears, the rider had to stop, remove the wheel, flip it around, and remount the wheel. When racers were allowed to use derailleurs, racing times immediately dropped.
  
  World War II
  
  Although multiple-speed bicycles were widely known by this time, most or all military bicycles used in the Second World War were single-speed. Bicycles were used by paratroopers during the war to help them with transportation, creating the term "bomber bikes" to refer to US planes dropping bikes for troops to use. The German Volksgrenadier units each had a battalion of bicycle infantry attached. The Invasion of Poland saw many bicycle-riding scouts in use, with each bicycle company using 196 bicycles and 1 motorcycle. By September 1939, there were 41 bicycle companies mobilized.
  
  During the Second Sino-Japanese War, Japan used around 50,000 bicycle troops. The Malayan Campaign saw many bicycles used. The Japanese confiscated bicycles from civilians due to the abundance of bicycles among the civilian population. Japanese bicycle troops were efficient in both speed and carrying capacity, as they could carry 36 kilograms of equipment compared to a normal British soldier, which could carry 18 kilograms.
  
  China and the Flying Pigeon
  The Flying Pigeon was at the forefront of the bicycle phenomenon in the People's Republic of China. The vehicle was the government approved form of transport, and the nation became known as zixingche wang guo (自行车王国)  the 'Kingdom of Bicycles'. A bicycle was regarded as one of the three "must-haves" of every citizen, alongside a sewing machine and watch – essential items in life that also offered a hint of wealth. The Flying Pigeon bicycle became a symbol of an egalitarian social system that promised little comfort but a reliable ride through life.
  
  Throughout the 1960s and 1970s, the logo became synonymous with almost all bicycles in the country. The Flying Pigeon became the single most popular mechanized vehicle on the planet, becoming so ubiquitous that Deng Xiaoping — the post-Mao leader who launched China's economic reforms in the 1970s — defined prosperity as "a Flying Pigeon in every household".
  
  In the early 1980s, Flying Pigeon was the country's biggest bike manufacturer, selling 3 million cycles in 1986. Its 20-kilo black single-speed models were popular with workers, and there was a waiting list of several years to get one, and even then buyers needed good guanxi (relationship) in addition to the purchase cost, which was about four months' wages for most workers.
  
  North America: Cruiser VS Racer
  At mid-century there were two predominant bicycle styles for recreational cyclists in North America. Heavyweight cruiser bicycles, preferred by the typical (hobby) cyclist, featuring balloon tires, pedal-driven "coaster" brakes and only one gear, were popular for their durability, comfort, streamlined appearance, and a significant array of accessories (lights, bells, springer forks, speedometers, etc..). Lighter cycles, with hand brakes, narrower tires, and a three-speed hub gearing system, often imported from England, first became popular in the United States in the late 1950s. These comfortable, practical bicycles usually offered generator-powered headlamps, safety reflectors, kickstands, and frame-mounted tire pumps. In the United Kingdom, like the rest of Europe, cycling was seen as less of a hobby, and lightweight but durable bikes had been preferred for decades.
  
  In the United States, the sports roadster was imported after World War II, and was known as the "English racer". It quickly became popular with adult cyclists seeking an alternative to the traditional youth-oriented cruiser bicycle. While the English racer was no racing bike, it was faster and better for climbing hills than the cruiser, thanks to its lighter weight, tall wheels, narrow tires, and internally geared rear hubs. In the late 1950s, U.S. manufacturers such as Schwinn began producing their own "lightweight" version of the English racer.
  
  In the late 1960s, Americans' increasing consciousness of the value of exercise and later the advantage of energy efficient transportation led to the American bike boom of the 1970s.  Annual U.S. sales of adult bicycles doubled between 1960 and 1970, and doubled again between 1971 and 1975, the peak years of the adult cycling boom in the United States, eventually reaching nearly 17 million units.
  
  Most of these sales were to new cyclists, who overwhelmingly preferred models imitating popular European derailleur-equipped racing bikes  variously called sports models, sport/tourers, or simply ten-speeds  to the older roadsters with hub gears which remained much the same as they had been since the 1930s. These lighter bicycles, long used by serious cyclists and by racers, featured dropped handlebars, narrow tires, derailleur gears, five to fifteen speeds, and a narrow 'racing' type saddle. By 1980, racing and sport/touring derailleur bikes dominated the market in North America. Fatbike was invented for off-road usage in 1980.
  
  Europe
  In Britain, the utility roadster declined noticeably in popularity during the early 1970s, as a boom in recreational cycling caused manufacturers to concentrate on lightweight (), affordable derailleur sport bikes, actually slightly-modified versions of the racing bicycle of the era.
  
  In the early 1980s, Swedish company Itera invented a  new type of bicycle, made entirely of plastic. It was a commercial failure.
  
  In the 1980s, U.K. cyclists began to shift from road-only bicycles to all-terrain models such as the mountain bike. The mountain bike's sturdy frame and load-carrying ability gave it additional versatility as a utility bike, usurping the role previously filled by the roadster. By 1990, the roadster was almost dead; while annual U.K. bicycle sales reached an all-time record of 2.8 million, almost all of them were mountain and road/sport models.
  
  BMX bikes
  BMX bikes are specially designed bicycles that usually have 16 to 24-inch wheels (the norm being the 20-inch wheel), which originated in the state of California in the early 1970s when teenagers imitated their motocross heroes on their bicycles. Children were racing standard road bikes off-road, around purpose-built tracks in the Netherlands.  The 1971 motorcycle racing documentary On Any Sunday is generally credited with inspiring the movement nationally in the US. In the opening scene, kids are shown riding their Schwinn Sting-Rays off-road. It was not until the middle of the decade the sport achieved critical mass, and manufacturers began creating bicycles designed specially for the sport.
  
  It has grown into an international sport with several different disciplines such as Freestyle, Racing, Street, and Flatland.
  
  Mountain bikes
  
  In 1981, the first mass-produced mountain bike appeared, intended for use off-pavement over a variety of surfaces. It was an immediate success, and examples flew off retailers' shelves during the 1980s, their popularity spurred by the novelty of all-terrain cycling and the increasing desire of urban dwellers to escape their surroundings via mountain biking and other extreme sports. These cycles featured sturdier frames, wider tires with large knobs for increased traction, a more upright seating position (to allow better visibility and shifting of body weight), and increasingly, various front and rear suspension designs. By 2000, mountain bike sales had far outstripped that of racing, sport/racer, and touring bicycles.
  
  21st century 
  The 21st century has seen a continued application of technology to bicycles (which started in the 20th century): in designing them, building them, and using them. Bicycle frames and components continue to get lighter and more aerodynamic without sacrificing strength largely through the use of computer aided design, finite element analysis, and computational fluid dynamics. Recent discoveries about bicycle stability have been facilitated by computer simulations. Once designed, new technology is applied to manufacturing such as hydroforming and automated carbon fiber layup. Finally, electronic gadgetry has expanded from just cyclocomputers to now include cycling power meters and electronic gear-shifting systems.
  
  Hybrid and commuter bicycles
  In recent years, bicycle designs have trended towards increased specialization, as the number of casual, recreational and commuter cyclists has grown. For these groups, the industry responded with the hybrid bicycle, sometimes marketed as a city bike, cross bike, or commuter bike. Hybrid bicycles combine elements of road racing and mountain bikes, though the term is applied to a wide variety of bicycle types.
  
  Hybrid bicycles and commuter bicycles can range from fast and light racing-type bicycles with flat bars and other minimal concessions to casual use, to wider-tired bikes designed for primarily for comfort, load-carrying, and increased versatility over a range of different road surfaces. Enclosed hub gears have become popular again – now with up to 8, 11 or 14 gears – for such bicycles due to ease of maintenance and improved technology.
  
  Recumbent bicycle
  
  The recumbent bicycle was invented in 1893. In 1934, the Union Cycliste Internationale banned recumbent bicycles from all forms of officially sanctioned racing, at the behest of the conventional bicycle industry, after relatively little-known Francis Faure beat world champion Henri Lemoine and broke Oscar Egg's hour record by half a mile while riding Mochet's Velocar. Some authors assert that this resulted in the stagnation of the upright racing bike's frame geometry which has remained essentially unchanged for 70 years. This stagnation finally started to reverse with the formation of the International Human Powered Vehicle Association which holds races for "banned" classes of bicycle. Sam Whittingham set a human powered speed record of 132 km/h (82 mph) on level ground in a faired recumbent streamliner in 2009 at Battle Mountain.
  
  While historically most bike frames have been steel, recent designs, particularly of high-end racing bikes, have made extensive use of carbon and aluminum frames.
  
  Recent years have also seen a resurgence of interest in balloon tire cruiser bicycles for their low-tech comfort, reliability, and style.
  
  In addition to influences derived from the evolution of American bicycling trends, European, Asian and African cyclists have also continued to use traditional roadster bicycles, as their rugged design, enclosed chainguards, and dependable hub gearing make them ideal for commuting and utility cycling duty.
  
  তথ্যসূত্র
  
  আরো পড়ুন
  Bijker, Wiebe E. (1995). Of bicycles, bakelites, and bulbs: toward a theory of sociotechnical change. Cambridge, Massachusetts: MIT Press. .
  Cycle History vol. 1–24, Proceedings of the International Cycling History Conference (ICHC), 1990–2014
   Friss, Evan. The Cycling City: Bicycles and Urban America in the 1890s (University of Chicago Press, 2015). x, 267 pp. 
   Tony Hadland & Hans-Erhard Lessing: Bicycle Design –  An Illustrated History. The MIT-Press, Cambridge (USA) 2014, 
  David Gordon Wilson Bicycling Science 3rd ed. 2004
  David V. Herlihy Bicycle – The History. 2004
  Hans-Erhard Lessing Automobilitaet – Karl Drais und die unglaublichen Anfaenge, 2003 (in German)
  Pryor Dodge The Bicycle 1996 (French ed 1996, German eds 1997, 2002, 2007)
  
  How I Saved The British Empire. Reminiscences of a Bicycling Tour of Great Britain in the Year 1901  A novel released by Ailemo Books in July 2015.  Author Michael Waldock.
  .  Library of Congress: 2015909543.
  
  বহিঃসংযোগ
  
   International Cycling History Conference (ICHC)
   Karl-Drais memorial
   Karl Drais seen by ADFC Mannheim – Focus on events in Mannheim, being the place of his invention. A 3-page Drais biography is available in more than 15 languages.
   Menotomy Vintage Bicycles – Antique bicycle photos, features, price guide and research tools.
   Metz Bicycle Museum in Freehold, NJ
   Myths and Milestones in Bicycle Evolution by William Hudson (accessed 2005-11-17)
   A Quick History of Bicycles from the Pedaling History Bicycle Museum (accessed 2005-01-06)
   
   Bicyclette of Harry John Lawson
   VeloPress has published dozens of books on the history of cycling and the bicycle.
   The Wheelmen organization
title: বাইসাইকেলের ইতিহাস