Common materials used for bicycles are
1. Aluminium - Aluminium's density is 2700 kg/m3, it is a relatively light metal. Pretty high corrosion resistant. The disadvantage is low strength and fatigue life. The advantage includes its low weight, relatively easy to weld and join. Its modulus of elasticity is estimated at 10 000 000 psi. 30
2. Steel - Steel's density ranges from 7850 kg/m3 on average. From the comparison with aluminum, it is heavier. When steel is used to make frame, the tube can be made smaller in diameter, thus reduce its weight. Steel can be welded quite easily. Older bikes have their tubes connected by lugs. Classic frames can be made with high quality steel. The disadvantage of steel is its high density and rust. A well taken care steel bike can last a lifetime. Its modulus of elasticity is estimated at 30 000 000 psi. 30
3. Titanium- Titanium density is 4506 kg/m3.It have a high strength to weight ratio. It is highly resistant to corrosion. However, its disadvantage is its difficulty to weld. Thus, high cost of workmanship. It is the chose of material if cost is not a factor to consider. Its modulus of elasticity is estimated at 16 000 000 psi. 30
4. Carbon Fibre - Carbon fibre density is lowest at 1780 kg/m3. It is easily molded into various shape, thus aerodynamic super bike are almost made of carbon fibre. It can be manipulated to be compliant and stiff and any direction depend on its weave. The disadvantage is cost of molding and should be not expose to direct sunlight for long period of time. carbon fiber heated from 2500 to 3000 °C (graphitizing) exhibits a higher modulus of elasticity (77,000,000 psi or 531 GPa or 531 kN/mm²).
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