Why a Bike Frame's Material Can Affect Its Handling

The right material for your frame - Bikeroom

The frame of a bike is what defines its soul more than anything else. Choosing the most suitable material for your needs is therefore crucial, especially considering that the primary riding sensations depend directly on the quality and geometry of the frame itself. For example, a low-quality carbon frame will tend to flex much more than a high-quality carbon frame. This is a noticeable factor, especially when descending at high speeds and tackling sharp turns.

In this short technical article, we aim to analyze the key element that defines a frame: its material. The most common options include carbon fiber, aluminum, steel, and titanium (or a combination of them). Depending on the material used to build a bike frame, it will have different characteristics that can influence its cost, comfort, weight, stiffness, strength, and durability. However, it's not just the material itself that determines these factors but also how it is utilized. But let’s take it one step—or one pedal stroke—at a time.

Credit: Passoni

Choosing the Right Frame

When selecting a bike frame, some key factors to consider include:

weight – the bike must be strong enough to support the rider's weight and any additional load, such as panniers for gravel bikes or other gear. Each material has its own characteristics, but it's important to accept the trade-off that stronger materials tend to be heavier. Another crucial factor is the importance of a lightweight bike. If you're aiming for maximum performance, this is something you’ll need to take into account;
intended use – if your goal is to race, a light yet stiff bike is the ideal choice. On the other hand, if you plan to travel by bike or take long road rides, durability will be a top priority. Bikes are designed with different features depending on their intended use, and achieving specific characteristics requires the use of particular materials;
durability – all materials wear over time, some more quickly than others. Steel, for example, rusts faster than aluminum if not properly maintained. Carbon fiber and titanium frames, on the other hand, offer excellent long-term durability. However, be aware that materials like carbon are less resistant to impacts compared to steel and aluminum.
budget – This is often the most influential factor when choosing a bike. To give a rough ranking from the most expensive to the most affordable, the order is: titanium, carbon, aluminum, and steel. As always, it's essential to balance cost with the intended use of the bike.

Credit: Orbea

Titanium Bike Frames

Titanium shares many of the properties of steel but is lighter, more resistant to oxidation, and undoubtedly more durable over time. The downside is that it is significantly more expensive to produce and requires many more hours of labor.

Manufacturing a titanium bike frame requires specialized skills. Like steel and aluminum, the titanium used in bike frames is an "alloy", often containing a percentage of aluminum and vanadium. Despite emerging at the same time as aluminum and carbon fiber, titanium never gained the same widespread popularity, primarily because its competitors are cheaper and easier to work with.

Nevertheless, titanium offers a superior stiffness-to-weight ratio and impact resistance similar to carbon. Additionally, nearly all titanium frame manufacturers offer a lifetime warranty against manufacturing defects.

Pros: strength, durability, oxidation resistance, ride quality, weight.
Cons: high cost, complex production process.

Prima Disco Passoni with a Titanium Frame Weighing 1,4 kg | Credit: Passoni

Carbon Bike Frames

Carbon fiber is undoubtedly an exceptional material for building bike frames. Its key advantages—stiffness, lightness, malleability, and high resistance to stress—define what is often called the "carbon era." While some materials are difficult to work with, carbon is highly moldable and can be shaped to meet a designer's exact specifications. This ability to customize both shape and material composition allows for aerodynamic, lightweight, stiff, yet comfortable frames.

Carbon was introduced by bike manufacturers in the early 1990s, after being tested on professional cyclists' bikes in the late 1980s. Its weight advantage over steel frames quickly made it the top choice. Initially, factors like high cost, moderate quality, and limited production methods slowed its mass adoption. Today, however, carbon fiber is present in almost every bike component.

Team Carrera, 1995: Claudio Chiappucci e Marco Pantani | Credit: Cinelli

Furthermore, when discussing carbon bicycles, it's essential to understand that the final product consists of two main elements:

carbo fibers;
resin (which acts as an adhesive to hold the fibers together).

Characteristics of Carbon Fibers

Although the thickness of a single carbon fiber can vary, it is always much thinner than a strand of hair. These filaments are grouped into tiny "bundles" that are woven together to form sheets similar to fabric. Since resin is often the weakest and most rigid part, the goal is to position the filaments as close together as possible.

The carbon used in bicycles is often unidirectional, meaning the angle at which it is laid is crucial. The orientation of the fibers determines the frame’s strength and stiffness in specific directions. For example, if force is applied against the fiber orientation, the structure remains strong and resistant. However, if the fibers are positioned at an angle that does not counteract the applied force, the frame may flex.

Some areas of the frame require more strength, such as the head tube, which absorbs significant forces to prevent fractures. Other areas, like the bottom bracket shell, need higher stiffness to optimize power transfer. High-end frames use stiffer fibers in this area compared to lower-tier models.

Manufacturers claim that their top-tier frames may contain up to 400 carbon fiber sheets. The performance of a carbon bike depends on a complex combination of the type of carbon fiber used, the quality of the resin, and the precision of fiber placement and orientation.

Pros: high stiffness-to-weight ratio, excellent resistance to temperature and corrosion, durable when properly maintained.
Cons: expensive, often irreparable if cracked, complex and labor-intensive production process.

Sarto Raso TC 2024 carbon fiber | Credit: Sarto Bikes

Aluminum Bike Frame

Aluminum frames are among the most common, as aluminum is widely used for bicycle components as well. It is not very "dense", making it ideal for lightweight structures, which is why it is perfect for bicycles. These frames are relatively inexpensive to produce, especially when compared to carbon frames, which take approximately 14 times longer to manufacture.

As with carbon fiber, aluminum comes in various forms and is always alloyed with small amounts of other metals and minerals. Regardless of the material choice, recent advancements in the industry have allowed for greater frame design customization, significantly improving ride quality. Not only can tube shapes be altered, but tube thickness can also be adjusted, making certain areas more resistant and others lighter based on performance needs.

Characteristics of Aluminum Bike Frame Production

The production of aluminum bike frames is essentially based on thinning the center of the tube to reduce weight while maintaining greater strength near the welds. So-called "constant thickness" tubes do not vary in thickness, ensuring uniform resistance at the expense of weight. Meanwhile, single, double, or triple-butted tubes allow the frame to withstand greater stress in thicker areas without adding excessive weight to the center. Specifically:

single-butted: one end is thicker than the rest of the tube, typically used for seat post collars.
double-butted: both ends are thicker than the rest of the tube, commonly used in the bottom bracket area and head tube.
triple-butted: features two levels of thickness at both ends. Due to the extra time required for this process, it is reserved for high-end frames, while constant thickness tubes are used for budget-friendly options.

Aluminum tubes can also be shaped using a process called "hydroforming", which allows metals to be molded through the use of a die and a fluid. The aluminum tube is placed inside a precisely shaped mold, and a high-pressure jet forces it to take on the desired form. This technique is commonly used to optimize tube shapes, increasing rigidity without the need for additional reinforcing material. Modifying frame design can help create a bike that is lightweight, durable, and comfortable.

Pros: Affordable cost, easier to manufacture, high strength-to-weight ratio, corrosion resistance.
Cons: Difficult to repair, lower long-term durability.

Trek Checkpoint ALR 3 2025 made with an Aluminum Frame

Steel Bike Frame

Until the 1980s, all bike frames were made of steel. Later, aluminum and then carbon fiber took over. Today, steel is used only for a select few custom classic bicycles, catering to a niche group of enthusiasts. There are two main types of steel used in frame production:

Hi-Ten - highly elastic with a very low strength-to-weight ratio, making it the primary choice for manufacturing budget-friendly bikes.
Chromoly (or "CroMo") - used for top-tier bikes designed for track racing, touring, and vintage cycling. This high-quality material is an alloyed steel with greater strength than Hi-Ten steel and can be shaped into tubes that taper or thicken, similar to aluminum.

Steel is affordable, durable, and strong, easily repairable and shapeable. Unlike carbon and aluminum, damage to a steel frame is easily repairable and rarely compromises the frame’s safety. Despite its strength, steel also has elastic properties that allow it to absorb shocks more effectively than one might expect. The downside is that steel is prone to oxidation (rust) and is significantly heavier than other materials. However, it is also more long-lasting and an ideal solution for carrying additional weight, such as panniers, racks, and accessories, without compromising the bike's performance.

Pros: Affordable and easy to maintain, durable, strong.
Cons: Heavy, prone to oxidation.