The Origami Crane 8 has a 52 tooth crank wheel and Shimano 11 to 34 tooth cassette. With the Kenda 20 x 1.75 tires, and a cadence of about 70 rpm, you will be right in your target range for speed. But, ultimately, your speed depends upon the energy you are willing to expend and your endurance. The fact that a bike folds, or the size of the tires, do not determine speed; the wheel size is only one part of the equation.