The material of the bicycle frame tube has evolved from the early chromium-molybdenum steel to aluminum alloy, and then to the application of composite materials such as carbon fiber. Besides, there are scandium alloys, magnesium alloys, titanium alloys, etc. Manufacturers are constantly developing new material formulas to enhance the design capabilities of the tubes and structures. Density is one of the important factors determining the weight of the frame. The lower the density, the lighter the frame. Thus, it can be seen that the density of chromium-molybdenum steel is higher, while that of carbon fiber-reinforced materials is lower. However, the frame not only needs to consider weight, but also needs to consider tensile strength, elastic coefficient, etc. Therefore, even if the density is low but the strength is insufficient, it is not acceptable. So, let's take a look at the differences between different material bicycle frame tubes together! 
In actual design, the diameters of the various bicycle frame tubes determine the rigidity, strength and weight of the frame. The wall thickness of the tubes also affects the strength and weight of the frame. A well-designed frame should emphasize both rigidity and strength, and also have areas to absorb vibrations. Therefore, it is necessary to use materials suitable for each functional requirement at different parts, and the combination technology of each material also poses a great challenge to frame manufacturers. 
Advantages and Disadvantages of Steel Frame: 
Steel is the material used for the frames of bicycles that have been in use for a long time. Its main advantages are that it provides good rigidity during long rides, the tubes have elasticity, there are various ways of tube jointing, the processing is good, welding is easy, no heat treatment is required, and the cost and price are relatively low. However, its disadvantages are that it is too heavy, and maintenance errors can cause rusting. The tubes are difficult to shape and there is a problem of metal fatigue. Although many alloy steels have achieved excellent results in terms of rigidity, elasticity coefficient, transmission performance, and stability at present, the drawback is still that they are relatively heavy. Chromium-molybdenum steel is common in steels, with high strength and easy tube drawing processing. Molybdenum can increase the strength of the steel and prevent it from reverting to brittleness; Chromium can resist corrosion of the steel, prevent rusting, and prevent high-temperature oxidation. Many fans of handmade steel tube bicycles recommend its excellent load-bearing capacity and the comfort of being suitable for long-distance riding. 
The processing performance is excellent. Chromium-molybdenum steel is a long-standing raw material for bicycles, and its research has been ongoing for a long time. Therefore, its processing technology has reached a relatively stable level. 
2. High strength. Based on the conclusions consistently reached by car enthusiasts, the strength of steel in the same volume is much greater than that of aluminum and titanium alloys. Therefore, the strength of a qualified steel structure can be relied upon. 
3. Comfortable ride. Steel is a metal with good elasticity. The frame made of steel can absorb the vibrations generated during driving. Therefore, the steel frame does not cause discomfort like the aluminum frame, and is particularly suitable for travel frames. 
4. The metal fatigue resistance of steel is much stronger than that of aluminum. Therefore, even under the same usage conditions, the lifespan of steel frames is much longer than that of aluminum frames. 
Of course, there are also some inherent drawbacks to steel structures: 
In today's era where there is an extreme pursuit of weight and lightweighting of equipment, the density of steel at 7.8 grams per cubic centimeter makes it terrifying for everyone. Although using lightweight steel allows for reducing the pipe wall thickness through the extrusion process, it is very difficult to reduce the weight of the steel structure to below 1600 grams. The weight of many aluminum frames is only around 1400 grams. This is because steel structures are rarely seen in racing car frames. 
2. Rusting. Compared to other materials, steel is more prone to rusting. Rusting significantly reduces the strength of steel and shortens its lifespan. (For example, in the case of BEARS frames, new electroplating treatment was carried out on the inner tubes to prevent rusting issues), therefore, in order to prevent steel from rusting, various measures must be taken. 
The above description explains the differences between various types of bicycle frame tubes. If you want to know more, please feel free to contact us at any time!