QUOTE(Mr. Z @ Oct 27 2016, 05:19 PM)
Don't misunderstood me bro, there is nothing to hate about the 20 inches, just that I don't feel all inspired by the size of the wheel on our uneven and awesome meteor rained road
😂
Also, felt that I would need a lot more pedal power to achieve the speed as a bigger bike, think someone posted their venture with big bikes few post ago..
The smaller wheels are easier to pedal actually. Only drawback would most probably be the speed. You can't compare all types similarly , to be honest. Each have their advantages and we choose which is the best for us or rather which suits our life style. In mountain bikes, the biggest chain ring is the 44 teeth and sometimes 42 teeth ( this in the triple chain ring setup, the double chain ring is even smaller at 36 teeth ) and the smallest rear cog is 11 teeth. This is hardest to pedal or needs the most effort. If you put this onto a folding bike, you will be free wheeling on a flat, you don't have enough high gear at all. Why, the wheels circumference is smaller.
Let's put this into a ride at the gear mentioned above. A 26 inch mtb with a 25mm tire circumference is 1913mm while a 20 inch wheel with 25mm tire is 1432mm. Respectively, the gear inches is 104 gear inches (GI) and only 80 GI on the foldie. The smaller the number GI, the easier it is to pedal (pedal effort) so that's why we normally put 53 teeth chainring on a foldie. If we use the 53 teeth chain ring the GI will increase to 96 GI , about the same effort but it is still easier than the mtb.
Let's presume there is a 57 teeth chainring, just to make the GI similar to the mtb, it will be 103.6 GI. OK lah almost the same effort
So, One turn of the crank on the mtb is 44 divide by 11 cogs at the rear means 4 turns of the wheels. This means one turn will make you travel 4 x 1.93 meters which is 7.72 meters. while on the folding bike it will be 57 divide by 11 cogs , means 5.18 turns multiplied by 1.43 meters which amounts to 7.4 meters. Quite near, right?

Hypothetically, we are pedaling with the same effort and GI. So, the folding bike is NOT slower than an ordinary bike if we set all the gear ratios , tire size equally.
BUT in actual, we never set the folding bike equal due to cost. It can be expensive. Another disadvantage of the smaller wheel is stability on roads, especially going over cobble roads, uneven potholes and fast downhill. As for roadbikes, why are they faster? That's because averagely, the weight of their bikes are less than 10 kgs with some a mere 7 kgs where else an average foldie is 13 kgs. Their tires can go down to 1cm wide but off course so can a foldie. The biggest advantage roadies have is off course the level of their bike's componentry, even the lowest grade component is far better than an average folding bike's components. All this makes road bikes quite effortless to pedal compared to a folding bike and even if we put in the same components as roadbikes, we still lose because we still have to carry an extra few kgs load (the bike itself) and also we cannot out pace them on downhills due to their bigger wheels (roadbike's are almost 29 inch) and also they too use 53 teeth chain rings.
That's why, many folding bike kakis migrated to road bikes because they cannot stand others faster than them and on the other side, many roadies also buy foldies because they are bored with the white line fever. What they see is only the white line of the road and they never notice what's happening beside them while riding.