How to Reset a Bicycle Speedometer & Tire Size

How to Reset a Bicycle Speedometer & Tire Size
Cycling computers come in a variety of styles from simple to complex and, depending on their design, can measure many parameters of a cyclist's performance. The primary function of a cycling computer is to measure speed and distance. To do this accurately, non-GPS models must have an accurate reading of the tire size used by the bike entered before use. Since cycling computers typically use non-rechargeable batteries, it's often necessary to reset the computer when replacing the battery.


Difficulty: Easy

Things You’ll Need:
  • Cycling computer
  • Manual or online access to the manual
  • Ballpoint pen
Step 1
Determine the size of the tire used on your bike. You don't need any special tools to do this. Every bike tire has the size stamped on the sidewall of the tire. There will be two numbers you'll need to note, separated by an "x." The first number is the diameter of the tire, the second is the width. Common road size tires are 700x23 (mm).
Step 2
Refer to your cycling computer's manual to find out the tire's circumference. This is usually listed in chart form--simply find the circumference that matches your tire's dimensions.
Step 3
Enter the circumference on your cycling computer. The exact method used to do this depends on the brand and model of cycling computers, of which there are dozens on the marketplace. An example of how this usually works would be this (used for the Cateye Mity 8):

1. Clear the computer by pressing the MODE, START and SET buttons at the same time.
2. Choose your unit of measurement (km or miles) by pressing the MODE button.
3. Press the MODE or START button until you have the correct tire measurement indicated on the screen, then press the SET button to lock in your choice.
Step 4
Reset your computer by following the method listed in the manual. In the case of the Cateye Mity 8 we used as an example, you press and hold multiple buttons at the same time. Some computers require you to press a small reset button on the back of the computer with a pointed-tip object, like a ballpoint pen.

Article Written By Nichole Liandi

Based in Virginia, Nichole Liandi has been a freelance writer since 2005. Her articles have appeared on various print and online publications. Liandi has traveled extensively in Europe and East Asia and incorporates her experiences into her articles. She holds a Bachelor of Arts in history from West Virginia University.

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