Although aluminum is now the most prevalent material in biking these days, up until the 1980’s, most mountain bike frames were made of steel.
Slowly, the market demand for lighter, stronger, and rust-resistant bike frames coupled with advances in aluminum metallurgy led some manufacturers to make the switch. Soon, most steel-frame bikes had aluminum parts in the form of brakes, derailleurs, stems, lightweight wheels, handlebars, and seat posts.
It wasn’t long before most bike manufacturers switched entirely to aluminum!
Although both steel and carbon fiber have come a long way , aluminum bikes remain an enthusiast favorite.
In the modern era, advancements in alloying technologies are bringing aluminum bikes to new heights by amplifying their properties.
Aluminum is the most widely available lightweight bike frame material. By comparison, steel bike frames have, on average, three times the weight of aluminum ones. Due to its naturally low weight, aluminum remains an ideal and affordable choice for racing and mountain bike frames.
Due to aluminum’s lower strength compared with steel, titanium, and carbon fiber, aluminum bike frame tubes often have thicker walls. Though this does not necessarily provide an advantage over other frame types, thicker-than-standard tubes can be used in aluminum bike frames without making them significantly heavier.
Carbon fiber, of course, has an edge on aluminum in terms of weight. But for a mountain biker, sometimes a little weight is a good thing.
Downhill racers often prefer aluminum over other materials. The additional weight and formability properties allow the rider to maintain the proper inertia to keep the bike steady and to maintain control at high speeds. Weighted aluminum frames make it easier to find the sweet spot.
Aluminum is a widely used material and is infinitely recyclable, so its price compared to other materials is very competitive.
Well-rounded, lightweight, and affordable, aluminum bike frames are the ideal choice for both beginner and expert-level mountain bikers.
Plus, aluminum is not prone to rust, unlike steel-framed bikes. This resistance makes aluminum a lasting and low-maintenance choice for mountain bikers and other riders who often expose their bikes to harsh elements.
For trail and downhill riders, the somewhat flexible, forgiving nature of alloyed frames help provide comfort during extremely bumpy terrain or at high speeds.
Alloys Used in Mountain Bikes:
2xxx series: 2xxx series alloys are not usually used for frames. They are easily welded and heat-treatable, but are more suitable for use in components such as bars, seatposts and stems – parts that usually have less butting. Alloy types you will likely encounter are 2011, 2014 and 2024.
6xxx series: 6xxx series alloys are intermediate strength aluminum alloys. In general, they are weaker than either a 2xxx or 7xxx series alloy, but are more easily forged, machined, welded, and formed. You will find them usually in lower cost aluminum alloy frames. 6061, 6063 and 6082.
7xxx series: Most commonly found in the aerospace industry, 7xxx series aluminum alloys are an incredibly high strength alloy that exhibits great resistance to the outdoor elements. The most durable of all bike frames are made from this series’ alloys.