Balance on a Penny Farthing bicycle
A couple of months back my employer wrote a blog post where they interviewed me to ask me some quick questions. It is actually part of a series of such posts, with several of my colleagues featured in their own post and the idea being to help our users get to know us better.
Take a spin #behindVivaldibrowser with Ruarí Ødegaard
Take a spin #behindVivaldibrowser with Ruarí Ødegaard [Gemini mirror of the above]
What is a Penny Farthing?
In the article there is a picture of me standing with my penny farthing and references to my riding it around town here in Oslo (along with my unicycles). For those not familiar with the term, the penny farthing is the original "bicycle"—in English at least, with earlier human powered, wheeled devices using the French term "velocipede". Penny farthings are distinctive in having one very large wheel at the front and a small one at the back. The large front wheel is a simple solution to greater speed without reliance on a more complex (and hence potentially less reliable) gearing systems. One revolution of a big wheel travels further and hence faster for the same pedalling speed. It also has the added benefit of providing a more comfortable ride because the large diameter wheel clears gaps in the road surface that would have a greater affect on a small wheel. Keep in mind that these bikes evolved in a time before widespread pneumatic (air-filled) tyres, on low quality roads, so this was even more important historically. The back wheel being small is due to weight saving. Since most of your weight is over the big, leading wheel, you still get the majority of the benefit of a comfortable ride without needing two big wheels.
The nickname "penny farthing" is actually a reference to these vastly different wheel sizes. In older British money, the penny was pretty large compared with the tiny farthing coin, and if you placed a penny and a farthing next to each other, they do look like a silhouette of this style of bike. Other names include "High wheeler" or "ordinary" bike (more on that later).
How do you balance one of these bikes?
In the few comments to the blog post, one of the responders (edwardp) asked me the question,
I've seen antique photos of similarly-styled bicycles (the yellow bicycle in the photo above). How does one balance themselves on such a bicycle?
Initially I did not answer this because I felt like I had nothing really to say other than, "umm… you just do?". Today however another user followed up also looking for a response, so I felt bad that I had not replied in such a long time. I sat and thought a bit more about it and suddenly realised I did have a bit to say after all. The following is a copy of my reply to the user for anyone else who might be interested.
@edwardp, @ingolftopf: When cycling at a constant speed, balancing for the most part is like a normal bike, in fact it anecdotally feels to me like it is easier. You can balance a bike like that at a lower speed than most people could balance on a normal bike. The extra height likely helps, perhaps in much the same way that it is easier to balance a broomstick than a pencil on your finger. Though I do not know enough about the physics of inverted pendulums to be sure.
That said, the reason I mention "at a constant speed" is that the obvious issue with these types of bikes is that you sit very near the balance point. Thus if you were to brake suddenly you could very easily get thrown over the handlebars. This is possible on a "normal" bike but is less common and requires harder braking and/or a steep downhill. Safety (or lack there of) due to this type of accident is one of the main reasons why these types of bikes have largely died out. such accidents were common in the past and from such a height you can seriously hurt yourself. Indeed modern style bikes were initially called "safety bikes", while bikes like those like mine were typically referred to as "ordinary" bikes during the crossover period where the modern style started to become more popular. Even to this day, fans of these older style bikes often continue to refer to them as "ordinary bikes". 😆
One interesting thing about riding such a bike is that you have to learn how to handle it in situations where something unexpected happens, like hitting a bump in the road that you did not notice. The the instinctive response and the correct one are very different. Most people will tend to stop peddling, slow down or even brake. All of these are a mistake. You should actually speed up! This is because the bump will slow your wheel down but your body will be less affected and continue to travel at at much the same speed due to your greater mass (and hence momentum), causing you to potentially be tipped over the handlebars. By pedalling faster you counteract this. Obviously when something "unexpected" happens you do not have time to think this out. The reaction must be so quick that for an outsider it looks instinctive (in reality it is just well learned behaviour from lots of experience). As as a rider of unicycles (for years) where the same situation is even more common (you are constantly correcting for falling forwards or backwards) this does now feel normal and natural to me, so I have had very few problems but I know of others who struggled to learn this behaviour and have come off their bike lots of times before they learned to overcome their instinct to slow down.
Anyway, I hope that answers your question and sorry for the slow reply.
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/gemlog/