Technical advances are making the already popular sports of cycling and
mountain biking even more fun. Major improvements in cycling technology,
notably in suspension and braking, already make for a safer and more
comfortable ride, but it is in the field of materials science where the real
impact is felt. Sciencebase guest writer
Michael Marshall takes us on a smoother than smooth ride through the latest
material gains in cycling technology.
Cycling has enjoyed a resurge in popularity over the last few decades,
mostly due to the increasing interest in mountain biking. This has been
matched by considerable improvements in cycling technology, notably in the
fields of suspension and braking. However, some of the most crucial advances
have been in the field of materials science; bikes nowadays are made from a
wide range of different substances, with strikingly different properties and
capabilities.
Traditionally, bicycles were made from steel, which is simply an alloy of
iron and carbon. Steel is extremely tough and fatigue-resistant, and also
has the key advantage of excellent damping properties. This means that much
of the bumpiness of the ride is absorbed within the frame, rather than being
transmitted through to the rider, and it consequently feels smooth to ride.
There are many different types of steel, often with extra substances added
to the alloy in small quantities. I have to confess an allegiance; my own
bicycle is made of CroMo steel, which contains chromium and
molybdenum and is consequently very strong and light.
Furthermore, when it breaks it does so suddenly and rapidly; steel has the good grace to crack slowly, giving the rider a chance to spot the damage and obtain a repair. You can also use a good quality, strong rust remover on the steel frames to avoid and fix rust damage.
However, steel has fallen out of favour with manufacturers. This is partly
because it has a tendency to rust, but principally because of the high costs
of steel frame manufacture. In its place, aluminium has swept the board to
become the most widely-used material, principally because aluminium frames
are easy to manufacture. The vast majority are assembled by the Tungsten
Inert Gas (TIG) welding process, which was developed in the late 1940s.
TIG is a form of electric arc welding, in which two electrodes are brought
into contact and a large current passed through them. The current produces
intense heating; when the electrodes are separated, the current travels
between them through the gap, forming a high-energy arc. This arc can reach
temperatures of 2000-3000 Celsius.