There are 4 criteria in choosing the most suitable folding bike for you, according to foldingbikeguy.com.
1. Folding Mechanism
There are basically 3 types of folding mechanisms for most, if not all, folding bikes.
(a) Split Fold Mechanism
This is the most common mechanism, in which the bike is folded in half. It does this with a hinge built into the centre frame of the bike.
Pros: Functions the best in almost all situations. Relatively quick to fold away.
Cons: The most bulky when folded. Thus, suitable only for people with large enough storage space (in vehicle or elsewhere).
(b) Triangular Hinge Mechanism
Containing both hinges and clasps, bikes with this kind of mechanism is folded in a particularly compact form and it does so in an intricate manner.
Pros: Takes up the least space and thus, useful to carry on public transport.
Cons: Due to the intricate nature of its folding mechanism, it takes more time to fold away and is slightly more complicated to do so.
(c) Break Away Mechanism
Bikes with this kind of mechanism splits entirely into 2 separate pieces, making it the rarest of the three mechanisms. Foldingbikeguy.com says only a small minority use bikes with this kind of folding mechanism due to the fact that it takes a far longer time to fold compared to the first 2 types and hence, it can become a tedious task to do so.
2. Frame material
Foldingbikeguy.com lists down 4 most popular types of frame material for folding bikes.
(a) Aluminium
Pros: Does not rust and is relatively lightweight. Makes for a good hybrid.
Con: Not the strongest material
Bottom line: An aluminium frame has been the choice of bike users for many years.
(b) Titanium
Pros: Very durable. Vibrates very little as titanium frames are the most stable ones.
Cons: Expensive. Weighs more than other frames.
(c) Carbon Fiber
Pro: The lightest frame for a bike.
Cons: The most expensive. Easily damaged.
(d) Steel
Pros: More durable than aluminium and rust-proof over time.
Con: The heaviest material compared to the other frames.
3. Size
Foldingbikeguy.com advises that you choose a folding bike that is fully flexible and can be adjusted to your size, among others. In terms of wheel size, there are four: 16", 20", 24" and 26", with the smallest size being the most flexible but unstable while on the road, and the largest (normally used for mountain bikes) being the most stable but at the same time, also cumbersome to carry around. The wheel size that offers good manoeuverability, agility and portability is the 20".
4. Gears
To choose or not to choose a folding bike with gears? Foldingbikeguy.com gives the pros and cons on either option.
(a) Bikes with gears
Pros: Have a high top speed, accelerate quickly, and can go up and down hills with much efficiency.
Con: Liable to break down, but if you prefer bikes with gears, it is recommended to get one with 3 to 8 gears.
(b) Bikes without gears
Pros: Reliable, especially for daily commute. Have a top high speed.
Con: Due to the fact that they operate at a single speed, they are slow at accelerating and not easy to traverse hilly areas.