Most current bikes are made of one or blends of three materials: steel, aluminum, and carbon fiber (carbon). Our frame experts compare the performance and benefits of these materials.
Learn More About Bicycle Frame Materials
Steel, the most traditional frame material has been used by framebuilders for well over a century. Many types of steel tubing are available and the material is easy to bend and shape. Plus, there are myriad methods of assembly, making steel very adaptable to cyclists' needs. Steel also offers excellent ride quality, durability, is easily repaired and affordable.
If there's a knock on steel, it's that it tends to be heavy. And, while there are new steels almost impervious to corrosion, most types can rust if treated carelessly (protect that paint job!).
High-quality steel frames integrate great design, superior assembly and better alloys in the tubing. A popular quality steel for bicycle frames is American SAE 4130 steel, better known as "chrome molybdenum," and referred to as "chromoly" or "chrome-moly." These frames are famous for their combination of responsiveness and comfort.
Aluminum is a very popular frame material. Aluminum bicycle frames are light and relatively inexpensive.
You may hear that aluminum has a more jarring ride than the other frame materials. But, while this used to be the case in its early years, it's not a problem today thanks to new aluminum alloys, tubing enhancements and improved construction techniques like hydroforming (shaping tubes with high-pressure water). These characteristics allow the frames to absorb shock better than ever while still offering the lively ride that makes aluminum so popular. And, unlike most steels, aluminum won't rust; another advantage.
Carbon fiber (also called "carbon" or "composite") is unique because it's not a metal. It starts out as a fabric (or sometimes just a thread that's woven into fabric) that's impregnated with a glue called resin. The resulting material can be turned into tubes or shaped in molds and is usually cured with pressure and heat, turning the material into a solid structure. Frames made of carbon are extremely light, stiff, and durable.
Carbon's greatest advantage is that it can be manipulated essentially in endless ways (because builders can orient the fabric strands however they want), which means it can be fine-tuned to provide just about any ride qualities desired. So it's possible to achieve supreme lightness with outstanding rigidity (for maximum pedaling efficiency) and top-notch compliance for comfort, too. What's more, carbon is impervious to corrosion and can be built into beautiful shapes producing stunning looking bicycles. Because the building and design process are more complicated than metal frames, carbon tends to be on the high end of the cost spectrum.