How to Use the Fixed Gear Chain Length Calculator

This tool calculates the precise length of chain required to fit your single gear setup.

Step 1: Find Your Chainstay Length

Since fixed gear bikes have rigid frames, this is a simple, fixed measurement.

• Measure: Measure the distance from the center of your bottom bracket axle to the center of your rear axle.
• Input: Enter the value in the Chainstay Length box and select either mm or inch.

Step 2: Input Your Gear Sizes

You only need to know the number of teeth on your single front chainring and your single rear cog.

• Chainring (Teeth): Enter the number of teeth on your front chainring (e.g., 48 or 46).
• Cog (Teeth): Enter the number of teeth on your rear cog (e.g., 16 or 17).

Step 3: Interpret the Results

The calculation uses a geometric formula to find the exact loop length required.

1. Recommended Length:
   • This is the minimum number of links you need to buy and install.
   • Because you cannot use partial links, the calculator rounds the precise geometric requirement up to the next even number of links.
2. Exact Links:
   • This displays the precise decimal number of links calculated by the formula (e.g., 96.45 links). This is useful to see how close your setup is to requiring the next link size up.
3. Physical Length:
   • This shows the linear distance of the required chain length (in inches or mm).

Note: Unlike derailleur bikes, this calculation is based on the assumption that you will tension your chain using horizontal dropouts or an eccentric bottom bracket to achieve the correct tightness, as there is no derailleur to manage slack.