The torque of a bike is determined by its rider.
Torque mainly affects the rotational speed of a bike. The more powerful the torque, the faster the acceleration. Both of these components help determine how fast a bike can go and how long a rider can hold his top speed. There are many factors that help determine bike torque, such as gear ratio, leg length and crank arm length.
Force and Lever Arm
Torque is mainly composed of a force and a lever arm, which is the distance between the line of action and the axis of rotation. In terms of bikes, human power determines the force of how fast the wheels turn. The bar that connects the pedal to the cog is the lever arm, and the action of the rider putting force on the pedal is what produces the torque on a bike.
The torque can determine the power produced in a bike by determining the RPM, or revolutions per minute. Although RPM is the point where the bike torque begins to drop off, it does not mean the power of the bike cannot still rise. For example, when a rider rides extremely fast downhill but feels like she cannot pedal any more, she has reached her peak torque but the power still rises.
Since the torque of a bike affects acceleration, it also affects the speed. Specifically, the more torque power a bike has, which can mean the more torque power the human engine of the rider specifically has, the faster it can go.