Riding my bicycle the other day, I thought "having learned how to ride a bicycle in the past, for me the experience of riding a bicycle is just like riding a bicycle." And then I thought, what did we say before bicycles to capture the concept of a difficult skill that is (nearly) impossible to forget once mastered? While there are phrases like second nature that might capture this, I'm specifically looking for a simile.
Before "it's just like riding a bike," people generally said, "just like swimming" or "just like skating." Those idioms did not appear until after the invention of the bicycle, but just barely, so riding a bike was not yet familiar to most people. The similarity of biking to skating was noted during the first bicycle craze.
The Velocipedomania is spreading, and we may expect shortly to be as familiar with these new conveyances in London as in Paris. In America, also, velocipedes – or bicycles as they are called – are becoming very popular . . . . I may mention, by the way, that the art of sitting and working a velocipede is by no means easy to acquire, and intending velocipedists may prepare themselves for sundry hard falls and bruises. It is, in fact, just like skating, very difficult to learn at first; and easy enough when once the knack is acquired.
The Royal Cornwall Gazette (Truro, England), April 1, 1869, page 8.
An early example of a simile using both swimming and skating.
Political crowing is a good deal like swimming and skating – when once you learn how, you never forget, no matter how long the interval between your efforts.
The Burlington Free Press, March 21, 1871, page 2.
The ease or recalling how to ride a bike after a long absence was noted as early as 1896.
“Don’t buy any season tickets,” suggested a practical looking girl, “but take out a wheel for an hour’s practice. If you can’t ride almost as well as you did when you left here, I’ll pay for your lesson. One never forgets how to ride. You think you have, but the minute you mount it all comes back in a flash, and while you may feel a little nervous at the start, you will get over that after taking two or three turns. At least, that’s what I have been told, and I should like to see it tested.
The Sun (New York), January 12, 1896, page 30.
The earliest example I've found of the now-familiar idiom appeared in 1915.
I can skate all right. There used to be an empty lot next to where I lived when I was a kid and ice skating’s one of those things you never forget, like swimming and riding a bike. So, while others were tuning up, I gave a little exhibition all my own. All the women, except one, were green with envy.
“Mollie of the Movies,” Alma Woodward, The Evening World (New York), December 17, 1915, page 22.
From some light research I've done, I haven't found any definitive answer to this question. I have tried to think what would people before the invention of the bicycle use as an equivalent and, because the bicycle was one of the first wheeled transports, I believe that the only thing that can be compared is the horse.
Horse riding is not an easy skill, but it's not easy to forget once you learn how to do it. It's almost like riding a bicycle. According to the wikipedia article on the history of the bicycle, the term bicycle was coined in France in the 1860s". Any similar simile should have existed before the word bicycle even existed.
I did an Ngram search on the hypothetical term 'like riding a horse' compared to 'like riding a bicycle' that brought the following results:
Also, according to Google Books, the first printed example of the idiom was in 1917 and then also observed in 1933:
November 1917, Boys’ Life, pg. 6, col. 2: “It’s like riding a bicycle,” Ritter argued. “You never forget.”
7 May 1933, Springfield (MA) Sunday Union and Republican, “Trouble with Roller Skates Is They Roll” by Weare Holbrook, pg. 5E, col. 7: “They say it’s like riding a bicycle,” I muttered encouragingly. “Once you learn how, you never forget it.”
I'm not sure if this answers the question, but I'm very curious to know if there really was a similar idiom before the invention of the bicycle.