When purchasing a new bike it can be a bit of a minefield. There are so many different options out there now, but by far the most important consideration should be the frame. As components wear out they are replaced, whereas your frame will be the lasting piece and therefore the most important.
Frames can be made from different materials, the most common being aluminium, carbon, titanium and steel. Each one has its pros and cons, depending on your budget and intended use.
What is your budget? Is weight a priority? Is it a bike that you intend to replace after a couple of seasons or keep going for 10+ years? Once you’ve answered these questions it will help to narrow down the type of frame that is best suited.
For example, if you’re just getting into cycling, you’re an aspiring road racer but with a low budget then aluminium would probably be the best for you. Its light (relatively), stiff and affordable. Carbon however would generally be lighter, absorb more of the jarring from the road but comes with a higher price tag. If, however, you’re looking for a long distance tourer, and you’ve a nice healthy budget then titanium would be the material of choice, it has a lovely smooth ride and is highly resistant to the elements. Steel would be a cheaper alternative, still providing that smooth ride but more likely to suffer in the rain and tends to add a fair bit of weight.
Let’s have a look at the different types of material and more of an in depth analysis of them.
Aluminium bike frame:
Aluminium would be the most common frame material, it is a relatively light weight, corrosion resistant material that has a high strength to weight ratio. It would be one of the most affordable materials, making it the material of choice for most budget conscious cyclists.
The downside however is that it tends to be a very stiff ride, it doesn’t absorb the road buzz as well as any other material therefore making it a lot more uncomfortable especially on dirt roads or longer rides where comfort is more of a requirement. It’s also tricky to repair, and aluminium fatigues more quickly over time. Thus, the best application of aluminium tends to be in entry level road and mountain bikes.
Carbon Fiber bike frame:
By far the most commonly used bike frame material for higher end mountain and road bikes (including virtually every bike being raced at the professional level), carbon fiber is a composite of carbon sheets that are bonded together in a mould using resin. The primary advantage of the material is that at a given stiffness, carbon fiber is significantly lighter than aluminium, steel, or titanium.
This lower density also means carbon frames do a better job of absorbing (rather than transmitting) road vibration, which translates into a more comfortable ride. And carbon fiber can be formed into complex shapes, giving bike makers greater creative design latitude. This is especially useful when trying to maximize the aerodynamic efficiency of a frame.
But that creative flexibility comes with a price. Although their cost has come down some in recent years, carbon fiber bikes are typically the most expensive. These frames are also more prone to fracture than metal, and once that happens carbon becomes fragile, and thus unfit to ride.
Titanium bike frame:
Another bike frame material popular with custom bike builders, titanium shares many of the same properties of steel, but has a greater resistance to corrosion and fatigue (it has the highest strength-to-weight ratio of all metals). That means you can build long lasting, lightweight frames and many titanium frame makers offer lifetime warranties against manufacturing defects.
Titanium is also renowned for its smooth ride quality that’s on par (if not exceeding) carbon fiber, making it an especially popular choice for custom road, touring, and hardtail mountain bikes. It’s also easier to repair than aluminium or carbon fiber, so if it ever does break, it can be fixed.
The downside is that titanium is a relatively rare (and thus expensive) bike frame material that’s labour intensive to work with, meaning these bikes are typically quite pricey.
Steel bike frame:
Once upon a time, steel was the bike-building material of choice. But its mainstream use has waned in recent years, with carbon fiber and aluminium frames now far more prevalent on bike shop floors. The primary reasons for steel’s decline: weight and cost. It’s heavier than both aluminium and carbon fiber, making it less desirable for high-end bikes. And it’s more expensive to mass manufacture than aluminium, hampering its use on lower end models.
However it might be the perfect bike frame material for someone who wants a custom bike without the high price tag of titanium. Indeed, it remains a popular material for custom builders, who revere it for its ride smoothing characteristics (especially for touring bikes). The reason for this is that steel is easier and less expensive to work with than carbon fiber, and it’s also denser and stronger than aluminium. That means you can use thinner walled tubes, and thus design vertical flex into a bike. Steel is also very durable, highly resistant to fatigue, and unlike carbon fiber and aluminium, can easily be repaired.
As bike-packing and bike-touring grow in popularity, steel is making a comeback as a great material. If it breaks mid-trip, there’s almost always a welding shop that can help you put it back together or bang out a dent in the frame.
Bamboo and more bike frame:
We won’t get into the other options too deeply here, but wooden bikes are no joke: Brands like Boo and Calfee have been building bikes out of bamboo for years, and while crashes can be costly, the frames are sturdy, lightweight, and surprisingly durable.
Alloys are popular in frame-building as well. Chromoly—chromium-molybdenum—is another common frame material used on many lower-end department store bikes. It’s a chrome-alloy steel that’s lighter than plain steel while maintaining the flexibility that makes steel a great material to use for frames.
Lastly, you may hear about scandium frames occasionally: They were popular a few years ago, though now they’re hard to find. Easton Sports introduced scandium as a cycling-friendly tubing material, and for a while, it was everywhere: Niner, Ridley and Kona all had scandium cyclocross frames in their catalogue years ago.
Scandium is mixed with aluminium in order to make it stronger but fell out of favour after only a few years on the market. Rumours around its fall from grace include a marketing issue because it was not well-understood compared to aluminium, or a knockoff problem that resulted in a bad reputation after the poorly welded cheap frames began to fall apart. Now, many bikes that are made with an aluminium alloy contain small amounts of scandium, but you likely won’t see it prominently mentioned.