How the bicycle got its spokes...

Believe it or not, the Tour de France has been running since 1903, only stopping for the two world wars. So how much have bikes changed over the last 111 years?

Philip Garsed, an electrical Engineering Student from the University of Cambridge spoke to Chris Smith about how the bicycle got its spokes...

Chris - When did bikes actually get invented?

Philip - Well, the one invention which really kicked it off was the idea of putting one wheel in the front of the other and then being able to steer one. That was in around 1817.

Chris - That's really rather recent, isn't it?

Philip - Comparatively, yes because if you think that the Romans and Greeks all had wheels, the idea of putting one in front of the other would seem possibly fairly obvious, but apparently not.

Chris - The eponymous bike is the penny-farthing. That's got to be the most famous design. How did someone come up with that and why did they come up with that rather enormous wheel at the front and the smaller one at the back?

Philip - If you look at the penny-farthing today, the whole idea seems completely ridiculous. They were dangerous. They were heavy, but actually, the whole idea was really quite logical because at that stage, we'd got to the point where the bikes with two wheels and there were also pedals, but the pedals were attached straight onto the front wheel. And if you do that, the only way you can change how fast you're going for a given speed of pedalling is by making the wheel bigger or smaller because there's no chain or gears or anything like that. And obviously, people like to go fast so the wheels got bigger and bigger.

Chris - So, when did they actually invent the bike as we know it?

Philip - So, the original idea happened in about 1817, but it took maybe another 70 or 80 years for it to get to something that we'd really recognise today. There were a series of key inventions along the way. There was the idea of pedals, tyres that cushion the ride, bearings that help wheels spin a little bit more easily, and things like chains and so on to just keep everything ticking along nicely.

Chris - But is it fair to say that really, by the end of the Victorian era, we'd arrived at all of those sorts of inventions and really, bikes haven't changed in the last 100 years at all.

Philip - Well, you have to be careful. By the end of the 19^th century, in about 1890, an entrepreneur from Coventry had put together all the key components - two wheels the same size, a chain, brakes, and of course, pedals. And you see within 10 years of that, anyone and everyone's riding bicycles - there's pictures of Elgar riding a bike and things like that. But it would be of course wrong to say that nothing has changed since. One thing happens and is slightly improved, and so, after another 120 years of slightly improvements, we have a much, much better machine than we had at the end of the 19^th century.

Chris - Let's look at the tyres for a minute. What about the sort of impact of vulcanisation of rubber, the ability to actually make a tyre that wouldn't be solid, it could contain air because that was an accident, wasn't it?

Philip - Well, there were a few things that happened there and this is one of the problems with invention. Pneumatic tyres like you have on a bike where they're filled with air were invented twice. There were a couple of reasons for this. Firstly, rubber is a very, very soft material when it's produced naturally. But for it to be useful for something like a bike tire, it actually needs to be quite durable. And so, this process of vulcanisation which was invented in about the mid-19^th century was actually very important for that being possible. But someone had invented the idea of a tyre for a cart, long before bikes were really a thing. But it never really took off because the rubber wasn't quite up to it and bizarrely, no one ever saw the possibilities in the invention. So, it turned out when a guy called John Boyd Dunlop actually came up with the idea of using this idea in a bicycle and it took off and was very, very successful. He actually took out a patent to protect his invention. It lasted for 2 years before someone, looking back through the historical archives, realised that it had already been done, so he lost it. But was otherwise quite successful with his invention.

Chris - What about gears and things like that? When did people come up with that idea and did they already know that the engineering and physics principles there or did that get invented for the purposes of cycling as well?

Philip - Well of course, by the time the bicycle was really taking off, there were steam engines and huge industrial machines. So, the actual principles behind gearing are quite straightforward. But the problem you have with the bike is it's a machine that isn't really that well looked after. It's exposed to the elements and more importantly, it needs to be as light as possible. The tricky thing there was waiting for chains and the actual physical gears to be strong enough and reliable enough to really be usable on a bike without just getting ground away to dust every time you tried to ride it. It wasn't really until that 1910s, 1920s, 1930s, that proper gearing like we know today really became practical.

Chris - Tell us to finish, why are bikes easier to stay up on when they're going along?

Philip - Okay, there's a couple of effects that go on here. One is, as you go faster and faster, the wheels spinning have an effect that causes you to stay upright if you try and tilt them. So, that's really useful, but it's only noticeable once you're going at a reasonable speed, maybe above 10 miles an hour. And so, another reason is simply the fact that you're steering all the time and you tend to lean around the corners. Of course, if you lean around a corner, anyone who's been fast around a corner in a car will know that you tend to get thrown to the outside of the corner. So, if you're cycling in a straight line, you're not really cycling in a straight line. Your just cycling in a series of wiggles which all add together to make something that looks a little bit like a straight line.