Determine your riding purpose
If you choose to use it during commuting or just make short trips and leisure trips in the city, then you need a lighter and more portable style. If you are a long-distance traveler, you need a strong folding bike with large wheels and frames.
Determine the wheel size you need
The wheels of folding bikes are usually 14'', 16'', 20'', 22'', 26''. The advantage of small wheels is that you can turn quickly. However, bicycles with 16-inch wheels are unstable during bumps. Any wheels that are too small (less than 14 inches) will conflict with a healthy bike geometry, which may mean that the bike is unstable or easily tipped over.
Conversely, a folding bike with a larger wheel size may not be as smooth as a small wheel when turning, but it is relatively smooth when riding.
Determine the frame you need
The material of the bike frame is aluminum, steel, chromoloy, titanium. Each bike frame has its advantages and disadvantages. If you prefer a lighter folding bike, you can choose an aluminum frame; if you prefer a folding bike with stiffness, you can choose a steel frame; if you prefer durable folding bikes, you can choose a titanium frame.
The folding bikes with bigger wheels tend to have smoother rides as compared to those with smaller wheels. However, the suspension mechanisms can help counter this by countering the friction of the smaller wheels. This will then add more pressure and weight. Suspension forks cam help shock absorption, provide you with greater flexibility and mobility.
Determine your folding method
Looks are important but do not sacrifice your ease of folding for that complex frame or folding mechanism that makes the whole folding bike idea redundant.
If you are an urban commuter who often uses public transportation and commuting bicycles, you need a bicycle that can be easily folded and unfolded. If you'll have to fold and unfold your bike frequently, you must Determine how often the bike will be folded and unfolded.
There are three folding methods of bikes in the market. These are half fold, triangle fold, and break away. The half fold is very easy to dismantle but not very sturdy. Bikes with a triangle fold are sturdy and easy to fold but not easy to ride. Lastly, those with the breakaway fold are the easiest to fold as they can be folded into a very compact size. The only downside of breakaway folding bikes is that they are harder to reassemble.