Most people with any interest in bikes will have at least a passing familiarity with the materials that are used to make them.
The sculpted, wind tunnel-honed lines of pro peleton bikes are unmistakably formed from carbon fibre. The skinny road bikes of old evoke images of bespectacled engineers in oil-stained overalls, squinting at steel tubes in complex jigs.
But do you know how these materials are used to make bikes that meet the needs of cyclists in the 21st century?
The basic diamond shape of a bicycle frame may not have changed significantly for more than 100 years, but the materials used in their manufacture have progressed considerably.
In this series of posts, I am going to look in detail at what bikes are made from: why those materials were chosen, who makes them, and how they are used to make a bike.
**UPDATE: The full list of ‘materials’ posts can be found on my new page dedicated to bike building: How To Build A Bike **
My first choice of material is steel, a metal whose own development over the past century has been interwoven with that of the bicycle.
So, whether you’re a man of steel or an Iron Lady (or any other superhero/1980s British prime minister), I hope you find something useful in this post.
What is steel?
The question you’ve always wanted to ask!
[quote style=”boxed” float=”right”]Men are like steel. When they lose their temper, they lose their worth – Chuck Norris[/quote]
Steel is an alloy of iron and carbon, amongst other elements. The types of steel used in bike manufacturer vary from lower quality metal (carbon or high-tensile steel), similar to that used in car production, through to specialised steel alloys.
Higher quality steel bikes are generally made from alloys. You might remember the name of one of the more familiar steel alloys, chromium-molybdenum or ‘chromoly’, from the sticker on your first bike. The highest-performing steel alloys these days include even more elements, such as nickel, niobium, titanium and copper.
The aim of the game in the development of newer steel materials is to increase strength, allowing bike manufacturers to use thinner tubing and therefore reduce the weight of the bike.
How are steel bikes constructed?
The frames of production steel bikes tend to be TIG welded together. The tubes are cut and mitred so that they fit against one another and then a weld is made to join them together. (TIG stands for ‘Tungsten Inert Gas’, chemistry fans)
Higher end and custom-made frames commonly use lugs in the joining of the tubes. Lugs are joining pieces that fit around the ends of tubes, allowing two or more tubes to be joined together. The lugs are then brazed onto the tubes in order to secure them into place. Brazing involves the use of another metal (such as brass or silver), which is melted to form the join, and then cooled to secure it.
I could try to argue that the use of lugs benefits the performance of the bike. The argument goes something like this:
The brazing material melts at a temperature much lower than steel. By brazing on lugs, rather using higher temperature TIG welding to join the tubes directly, you avoid the risk that the tubing is brought close to its melting point, which causes the metal to crystalise and can result in the seperation of its alloys. Hence, lugged joints are stronger (all else being equal).
I could argue that.
But the truth is, steel bike aficionados tend to like lugs for aesthetic reasons. They hide what would otherwise be ‘unsightly’ welds (although there are those that will write poetry about a well-formed visible join) and introduce style and individuality into what can otherwise appear a rather utiliterian object. The use of lugs, and their design, speaks to the framebuilder’s skill – they remind the owner of the bike, and anyone that sees it, that craftsmanship went into its manufacture.
And who doesn’t like to see a little bit of craftsmanship?
Who makes steel tubing for bikes?
The major manufacturers of steel tubing for bikes are Reynolds and Columbus.
Reynolds is based in the UK (who said we’ve lost our industrial base!). The company started life in 1841 as a maker of nails, before turning to bicycle tubing at the end of the nineteenth century. The firm patented the invention of butted tubes (whereby tube walls were made thicker, and therefore stronger, at the ends) in 1898. Their flagship product these days is Reynolds 953, which purports to benefit from being a ‘martensitic-aging stainless steel alloy’ with ‘tensile strength in excess of 2000 MPa’.
I’m guessing that means that it is strong and light.
Columbus has its origins as part of an Italian firm founded in 1919 by Antonio Luigi Columbo. In addition to making tubes for bicycle framebuilders (Edoardo Bianchi was an early customer), A.L. Columbo supplied a diverse customer base, from furniture makers to manufacturers of aircraft. In 1977, a dedicated firm, Columbus, was established to develop and manufacture specialist bike tubing. Being an Italian firm, Columbus has benefited from (and contributed to) the reputation for quality associated with Italian framebuilders.
It’s always difficult to decipher the website of an Italian manufacturer (it is – I used to come across them a lot in my previous career), even when they’ve been translated into English (or maybe because they’ve been translated into English). As far as I can work out, Columbus’s top of the range steel offering is called Niobium, but your guess is as good as mine as to how it is made or why it works…
Why do people choose steel for bicycle frames?
The main argument in favour of a steel-framed bike, particularly over a carbon fibre frame, is strength and durability.
Steel is resilient to the repeated stresses placed on the bike frame when riding (flex, for instance). It is tough, being resistant to cracks and impact. When dents or nicks do occur, with steel, they are less likely to turn into full-blown failures. If there is a failure, it tends to progress slowly rather than catastrophically (unlike carbon fibre).
A steel frame can be repairable. If a tube is broken or corroded, more often than not it can be repaired or swapped out and replaced with a new one.
If you’re planning on cycling around the world (what, you mean you’re not?), and hit an argali somewhere on the Mongolian steppe, you’re more likely to find a workshop in an Ulan Bator backstreet that has the tools to fix a steel-framed bike than a carbon one.
(An argali is the world’s largest wild sheep).
Using steel is probably the most cost-effective way to get a custom-fit bike made to suit your precise requirements and body shape.
Many people (and I include myself within that number) consider steel-framed bikes to be more attractive than those made from other materials (particularly carbon fibre). This is, of course, entirely subjective. The aesthetics will depend on the design of the bike, and who (or which factory production line) made it. There are countless steel-made atrocities; some carbon fibre bikes are attractive (yes, really).
On the whole, when buying a product, people like to know there was a human directly involved in its manufacture. They like to feel there is expertise, craftsmanship and care deeply imbued within its fabric.
In buying a higher-quality, or custom-made, steel frame bike, a cyclist is supporting and celebrating the craft of bicycle-making and doing their own little bit to ensure that it continues into the future.
What are the limitations of steel as a frame material?
The traditional argument against the use of steel in high-performance bicycles is weight. All else being equal (in terms of quality and purpose), a carbon frame will be lighter than an equivalent steel one.
However, we’re not all pro riders looking to save every last gram.
Add on the weight of components (which will be the same in each case), graciously accept that we do not have the hungry whippet physique of Bradley Wiggins and then acknowledge that we would ideally like the frame to survive more than one season on our pot-holed roads, and suddenly the weight differential of the frame material becomes a little less important.
Sign up to the Grimpeur Heureux e-mail list: it’s a steel…
So that concludes my appraisal of the use of steel as a bike-making material. I hope you find it interesting and enjoyable.
The Grimpeur Heureux (that would be me) has been considering purchasing a new road bike. I’ve been looking at a variety of options, including a custom steel framed bike, to be made by a local framebuilder. If you’d like to read more about that, you can find the post here.
Look out for the other posts in this series, as I look at carbon fibre, aluminium, titanium and more unusual materials (at least as far as framebuilding is concerned).
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In the meantime, I wish you happy and safe riding.