On the Schwinn cycle computer, you will find two buttons, one to the right and one to the left of display screen. Simultaneously press both those buttons and hold them a couple of seconds. The display on the screen will change to ‘Wheel Size Input Mode’.
Now you need to know the diameter of the wheels of your bike. Keep in mind that the diameter is same for both wheels. If it is a new bike that you are dealing with, you should be able to find the wheel diameter inscribed on both tires. However, if the tires are worn out, you will have to calculate the wheel diameter using a tape measure. Inflate one of the tires completely and then measure from the axle of one of the wheels to the point where the tire starts. Multiplying this measurement by 2 will give you the diameter of the wheel.
Convert the reading from the earlier step to millimetres. Calculate the circumference of the wheel by multiplying the diameter by 3.1416 which is the value of π.
Now you need to input this wheel circumference in the Schwinn cycle computer. While the display screen shows ‘Wheel Size Input Mode’, press the left button once.
In order to enter the first digit of the wheel circumference, repeatedly press the right button until you reach the desired digit. Move on to the next digit by pressing the left button once and then enter the appropriate digit as you did before. Continue until you have completely entered the wheel circumference.
In order to activate the ‘Km/File’ function, press the left button once. If you want to switch between kilometre and mile, simply press the right button.
To finish calibrating the Schwinn cycle computer, press the left button a last time.