What materials are the frame made of?

The most common type is the iron frame, but the iron frame is also divided into chrome molybdenum steel, high-strength steel, ordinary steel, and other components added to the iron frame. After adding these other components, it can be made into thinner pipes, making the overall frame lighter. On the basis of not reducing strength, frames made of materials other than iron, such as aluminum alloy, have emerged. In bicycle racing, frames made of titanium metal and carbon fiber materials are used.

Frame and height reference data:
14 inch -150-160 15 inch -155-165
16 inch -160-170 17 inch -165-175
18-170-180 19-175-185
20 inch -180-190 21 inch -185-195

Before 2009, almost all mountain bikes were 26 inch, until a certain automaker developed the world's first 27.5 inch/650B mountain bike in Washington, D.C., in 2009. Due to its ability to provide optimal handling, stability, safety, and performance for mountain bikes, a new wheel diameter revolution has officially arrived in the cycling industry. Major brands have followed suit to develop complete vehicles of this size, and the 27.5-inch/650B complete vehicle has gradually become the mainstream product in the bicycle market