Welcome to the third post in my series looking at the materials used to build bike frames.
Here are the links to the previous articles:
**UPDATE: The full list of ‘materials’ posts can be found on my new page dedicated to bike building: How To Build A Bike **
In this post we’re going to look at the metal that my superhero alter-ego would have his balls made out of: titanium.
And on that bombshell (egg-shell), we should probably move swiftly on….
What is titanium?
Holy cow. I’ve just found out that titanium was discovered in Cornwall at the end of the 18th century (thank you Wikipedia). And there was me thinking it was some sort of space age material.
It’s a metal (er, yes…), and despite my assumption that titanium bike frames were expensive due to scarcity of the metal itself, it is in fact the ninth most abundant element in the earth’s crust. In the metals-only league table (for I believe scientists do refer to such things with sporting analogies), it is the fourth most bountiful element (that’s according to Titanium.com – Wiki says seventh).
Titanium appears to have decided to play the role of sensible, straight-talking element, choosing the symbol ‘Ti’ within the periodic table (unlike those jokers, lead and silver).
Titanium obviously has something of an ego though, naming itself after the first pantheon of Greek gods and goddesses (known, appropriately, for their strength and stamina – much like the Grimpeur).
Where does it come from?
The largest producers of titanium are Australia and South Africa, with Canada not too far behind.
In nature, titanium is always bonded to other minerals. The two elements from which it’s worth trying to extract titanium, if you are a mining company (if you’re not, it’s probably not worth trying to extract titanium at all), are the minerals, rutile and ilmenite.
Nope, I hadn’t heard of them either.
How are titanium bikes constructed?
Titanium frames are made in much the same way as steel ones, using titanium tubes, cut to size and TIG-welded together (read about it in my article on steel bike frames here).
The tubes made to make bicycle frames are not made purely out of titanium (which either seems to be known as unrefined titanium or ‘commercially pure’ titanium). Instead they contain a small percentage of aluminium (3-6%) and vanadium (2.5-4%). These titanium alloys are stronger than the pure material.
Given the cost of titanium, production bikes tend to be at the higher end of the price and quality range. Although I don’t have any statistics to hand, you’d expect custom-made frames to form a higher proportion of all titanium bikes sold, versus those made out of steel..
Why do people choose titanium for their bike frame?
The traditional argument in favour of titanium over steel is weight: for equivalent frames, the titanium one will be lighter.
Proponents (such as those in this article from Bicycling magazine) talk about the different way that titanium flexes under stress. Apparently titanium has a ‘non-linear modulus’. In other words, it provides initial ‘give’, but then stiffens up as the force increases. The flex avoids a ride like a jackhammer; the firming up means you don’t lose out on responsiveness.
Titanium is corrosion-resistant – it doesn’t rust. Unpainted titanium frames look beautiful (in fact, there may be some sort of law that prevents them being painted.
Steel gets a lot of plaudits from its fans, but for some titanium aficionados, the belief in superior ride quality almost becomes an article of religious faith. For the alternative (or maybe, more measured) viewpoint, that it’s the skill of the builder, plus the choice of tire, seat and geometry, that determines how a bike rides, take a look at this article from Sheldon Brown.
What are the downsides of a titanium bike?
Cost, COST and, I’m afraid, C-O-S-T.
The basic cost of the titanium tubing required to form the frame can exceed that of a high-quality, finished carbon or steel frame.
You might also add that titanium is more difficult (read, costly) to repair than, say, steel, but there aren’t that many scenarios where this is relevant. It really is all about the cost at the time of purchase.
They do look very sexy though…. (if that’s your kettle of poisson).
What do you think?
So far in this series I’ve covered the three mainstream frame materials for most road cyclists (despite riding one myself, I’m sure most of you don’t have, or aspire to have, an aluminium-framed bike).
Do you have a preference for one material over another? Do we have more steel fans reading this blog, versus carbon lovers? Anyone own a titanium bike?
Let me know in the comments below!
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Photo credit: http://www.flickr.com/photos/31495901@N07/