Affinity Gear Calculation Chart

$ 20.00

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Finally! A reliable, accurate gear calculator for 700c wheel track bikes so you can spin the perfect gear ratio on the track or in the streets.

Most, if not all, gear calculation charts online and found in apps are not very accurate. The nerds at Affinity crunched the numbers and created a simple, easy to use wheel chart that generates 100% accurate calculations.

Rotate the durable plastic chart to choose your chain ring size. The window displays the results of your chain ring & cog ratio. Boom. Done.

• made in USA

• measures 8.5" in diameter

• 342 total calculations using a wide range of chain ring variants (47-65t), six cog sizes (12-17t) & three tire sizes

• results in both inches and meters


All the cool kids are doing it. You want to be cool, right?