The assembly of the two-wheeled iron frame can be based on the assembly method of ordinary bicycles and two-wheeled electric vehicles, that is, the assembly method of the main body of the frame and the components.

Frame materials have evolved from the earliest chromium-molybdenum steel, to aluminum alloy, and then to the use of composite materials such as carbon fiber. Others include scandium alloy, magnesium alloy, titanium alloy, etc. The industry continues to develop new material formulas , improve pipe fittings and structural design capabilities and innovate processing technology, just to make the frame lighter, stronger, more comfortable and more streamlined and beautiful. Density is one of the key factors that determine the weight of the frame. The lower the density, the lighter the frame can be. The density of chromium-molybdenum steel is 7.9, aluminum alloy is 2.6-2.9, titanium 4.5, titanium alloy 4.3-5.1, carbon fiber composite Material 1.6, magnesium alloy 1.7, it can be seen that chromium-molybdenum steel has the highest density and carbon fiber composite material has the lowest density. However, in addition to weight, the frame also needs to consider tensile strength, elastic coefficient, etc., so although the density is low, it is not strong enough.

The materials that can currently be used to make bicycle frames mainly include the following: steel, aluminum alloy, titanium alloy, magnesium alloy, scandium alloy, carbon fiber, etc. Generally, the frames on the market mainly include steel. Aluminum alloy, titanium alloy, carbon fiber. Scandium alloys and magnesium alloys are relatively new and emerging materials.