Andrew Ritchie, inventor of the Brompton folding bicycle, once said that perfect portable bike would be “like a magic carpet... You could fold it up and put it into your pocket or handbag". Then he paused: “But you'll always be limited by the size of the wheels. And so far no one has invented a folding wheel."
It was a rare --- indeed unique --- occasion when I was able to put Ritchie right. A 19th-century inventor, William Henry James Grout, did in fact design a folding wheel. His bike, predictably named the Grout Portable, had a frame that split into two and a larger wheel that could be separated into four pieces. All the bits fitted into Grout's Wonderful Bag, a leather case.
Grout's aim: to solve the problems of carrying a bike on a train. Now doesn't that sound familiar? Grout intended to find a way of making a bike small enough for train travel: his bike was a huge beast. And importantly, the design of early bicycles gave him an advantage: in Grout's day, tyres were solid, which made the business of splitting a wheel into four separate parts relatively simple. You couldn't do the same with a wheel fitted with a one-piece inflated(充气的)tyre.
So, in a 21st-century context, is the idea of the folding wheel dead? It is not. A British design engineer, Duncan Fitzsimons , has developed a wheel that can be squashed into something like a slender ellipse(椭圆) . Throughout, the tyre remains inflated.
Will the young Fitzsimons's folding wheel make it into production? I haven’t the foggiest idea. But his inventiveness shows two things. First, people have been saying for more than a century that bike design has reached its limit, except for gradual advances. It’s as silly a concept now as it was 100 years ago: there's plenty still to go for. Second, it is in the field of folding bikes that we are seeing the most interesting inventions. You can buy a folding bike for less than £1,000 that can be knocked down so small that can be carried on a plane —— minus wheels, of course —— as hand baggage.
Folding wheels would make all manner of things possible. Have we yet got the magic carpet of Andrew Ritchie's imagination? No. But it's progress.

折叠自行车的发明者安德鲁里奇布朗普顿曾经说过，完美的便携式自行车就“如同一张魔毯...可以折叠起来放入口袋或手袋中。”然后他停顿了一下又说道：“但你永远受到车轮尺寸的局限。而且迄今为止还没有人发明出折叠轮。“
这是一个难得的---确实是独一无二的时机---使我能够纠正里奇的断言。亨利 詹姆斯 威廉 格鲁特作为一个19世纪的发明家，事实上他的确设计了一个折叠轮。他的自行车，不出所料地命名为格鲁特便携式自行车。他的车架一分为二，大车轮可以拆成四块。所有部件都可恰到好处地装入奇妙袋，也就是一个皮套。
格鲁特之目的：解决火车上携带自行车的问题。现在，那岂不是听起来很熟悉？格鲁特目的是找到一种能制作出足够小巧自行车的方式以适合火车旅行。他早期制作的自行车是一个庞然大物。而且重要的是，早期的自行车设计（经验）给了他一大优势：在格鲁特那个年代，轮胎是坚硬的，这使得将车轮分为四个部件的商业制作相对简单。然而，要在一个车轮配一条充气轮胎的情况下，将车轮一分为四，是完全办不到的。
因此，在21世纪，难道折叠轮的理想就要胎死腹中了吗？事实并非如此。邓肯菲兹蒙斯，一名英国设计工程师，研发了一种能将车轮压扁得像一个细长椭圆。（挤压过程中，）自始至终，充气轮胎依然胀鼓鼓的。
年轻的菲兹蒙斯研发的折叠轮会投入量产吗？我对此一无所知。但他的发明却表明了两件事。首先，一个世纪以来，人们一直在说自行车的设计（空间）已达极限，除了循序渐进式的细节改善以外。这是一个愚蠢的观念，与100年前的“还有大量有待提升的空间”的观念一样同样愚蠢。第二，正是在折叠自行车领域，我们看到了最有趣的发明。你可用不到1000英镑买一辆折叠自行车，拆装之后体积非常之小，可以带到飞机上，不包括轮子，当然是当作手提行李。
折叠轮的发明历程表明：事物可以各种形式来加以表现是可能的。我们是否还有安德鲁里奇那样富有想象力的魔毯呢？没有，因为一切还在进步。