What You Need to Know About Bicycle Frames Part 2

Aluminium

It was around the 1970s when aluminium became ubiquitous enough, and began to be manufactured in large enough volumes to become economically feasible outside of military and aerospace applications. Today, aluminium frames are giving the steel ones a run for their money as they are gaining popularity thanks to the continuously decreasing price of this material over the years. Aluminium is inherently lighter than steel, but its also an easier material to work with in some respects. Steel tubes are usually of a uniform thickness throughout. The pliability of aluminium enables the manufacture of tubes that vary their thickness, or “gauge”, in different sections. This enables the bicycle to be of maximum lightness without resorting to exotic materials. The way it works is the tube sections that receive the greatest amount of load and stress are thicker than the sections where the load is less. This is known as ‘butting’, and it can occur in various ways depending on how high end the bike needs to be. A common example of butting is when a tube is thicker at the welded ends, compensating for the potential weakness where they are joined, while being thinner in the center. Obviously, the more variable the gauge the more expensive the manufacturing process, so perhaps it is best not to obsess about this too much when considering the matter of value for money.

Nevertheless, an aluminium frame is a good choice for those who don’t want a bicycle to cost an arm and a leg, but who still seek performance superior to that of a steel-frame bike. If you’re a beginner race cyclist, an avid cyclist in your free time, or a commuter who’s looking for some thrill on the way to work – an aluminium frame is a good bet for you. Yet, it is not without its downsides. First, the TIG welding that is necessary when working with aluminium is significantly more difficult than the welding involved in steel frame manufacture. This increases the chances of the frame having serious factory defects if you’re buying from a shady manufacturer. Second, even if the bike is built properly (which usually means that it was welded robotically), you better make sure that your favorite weekend route or your commute is predominantly good pavement. Aluminium is more subject to fatigue than steel, which means that constant abuse will weaken the frame faster over time. Add to that the fact that a minor incident that might damage the frame will be more consequential than with a steel bike. Repairing aluminium requires the skills and the tools that are not as common as you might have hoped, so you might be disappointed when you bring a damaged aluminium frame to your regular mechanic only to find out he can’t help. Another thing to consider is comfort, which is not a strong point for aluminium frames. The tubes have to be thick to get the right rigidity, making all that unsprung mass a perfect way to transmit all road imperfections directly to your body. If an aluminium bicycle is going to be your daily – consider a model with some kind of suspension.