Right, that's how you could plausibly have made one or two, as a palace amusement, or a circus act. It's a little surprising this didn't happen (as far as I know).

But efficient enough to go some distance, reliable enough not to need a full-time repair-man, and cheap enough to be sold to people who didn't already own a horse & carriage? That needed lots more technology.

> Right, that's how you could plausibly have made one or two, as a palace amusement, or a circus act. It's a little surprising this didn't happen (as far as I know).

You also need people to ride it. It wouldn't fly as a palace amusement because the king (and more importantly the little prince) would keep falling off. They won't have an incentive to value the skill until there is a horde of middle-class, 19th century, hipsters showing him up.

A circus act is more plausible, but only if there's some continuum of other simpler circus equipment leading up to this rather sophisticated bit of engineering.

Bamboo-frame bicycles exist today as a fashionable item, and as far as I can tell without having ridden one, they work for practical purposes just as well as metal-frame ones.

I suspect you could make a perfectly acceptable modern bicycle with 18th century technology, albeit not as durable. Metal axles aren't much of a problem. Light and strong wheels are trickier, but you could get away with solid wooden ones, or emulate modern spoke systems with sturdy leather strands. The chain is difficult point - leather won't cut it as you need immense tensile strength and rigidity - but if you didn't want to meticulously hand-craft a modern chain (possible but tedious), a direct-gear solution might be practically possible.

No, what was missing was the very concept that it would be a worthwhile thing to attempt to build. It would have taken an incredible visionary to follow the above steps, especially in a world where the poor quality of roads made such a device of questionable value. And anyone rich enough to afford such a thing was doubtless rich enough to afford a horse carriage - who in that set would aspire to pedal through the mud?

tl;dr expensive, flimsy bicycles are completely useless in a world with poor roads and deep wealth inequality.

> expensive, flimsy bicycles are completely useless in a world with poor roads and deep wealth inequality.

You make a last great point with this.

Without paved roads, rubber, decent springs; all of the shortcomings are amplified. The gear drive works, but if you have a wood wheel, with a wood axle, w/ wood cogs, the tolerances to be both comfortable and effective on cobblestone or dirt would be troublesome.

> Without ... rubber,

as a one-word piece of supporting evidence, let me just say - Boneshakers.

https://en.wikipedia.org/wiki/Velocipede#Boneshaker

Agreed. Vulcanized rubber tires appear to be the major missing component. Vulcanization wasn't discovered until 1839 [1] and the need to further improve ride comfort (from solid rubber tires) helped spur the creation of the pneumatic tire in 1888 [2].

[1] https://www.britannica.com/technology/vulcanization [2] https://www.britannica.com/technology/tire#ref117797

The existence of huge numbers of wooden scooters called chukudu in Democratic Republic of Congo and Rwanda disproves this. Apparently they are made with simple woodworking tools, transport 500 pounds and last 2-3 years.

The Chukudu is more practical and simpler than the penny-farthing. And the roads in the Democratic Republic of Congo are rough.

Leonardo da Vinci could have built a Chukudu in 1490.

I read one source that says metal ball bearings are used to attach the wooden wheels to the wooden axle. Makes sense, because otherwise the friction would probably make the device impractical.

Might not rubber belts have been possible instead of chains? Rubber was available 18th Century - maybe not in industrial quantities but still. In fact, latex was was available to the Mayans and Aztecs according to https://en.wikipedia.org/wiki/Natural_rubber#History

AFAIK you'd need vulcanization to make rubber belts practical, so wouldn't have been available much earlier than chains and sprockets.

Good design may not have made up for the "wealth inequality" aspect of ancient bike production ... but it could have surmounted the issue of bad roads: The Rungu 3-wheeled electric bike seems to be well suited to rough, off road, conditions:

https://electrek.co/2019/05/23/first-ride-rungu-three-wheele...

Leather "chains" were used on bicycles for a while, made from several small pieces of leather riveted together, in order to form ridges that gears could grab onto.

>he chain is difficult point - leather won't cut it as you need immense tensile strength and rigidity - but if you didn't want to meticulously hand-craft a modern chain (possible but tedious), a direct-gear solution might be practically possible.

Leather is good enough for motorcycle drive belts. Nowadays belt drive bikes use cogged composite belts, but once upon a time they were leather.

Leather belts would work fine if you made them wide enough. I'd expect a canvas belt to be used instead - wide again being key. I'd expect to need a the belt to be a couple cm wide to work. A chain is better, but this should work.

And the chain. The chain has more pieces in it than the rest of the bicycle by a significant margin. A safety bicycle could never have been created with out modern precision mechanical engineering and production.

You'd need good steel for spoked wheels too- without that you have heavy solid wheels instead.