FixedGears is a gear calculator for riders of single-speed and fixed-gear bikes. It calculates gearing for various chainring and cog sizes, cadence, speeds, skid patches (1- or 2-leg), alternate gearing (real).
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Note: Current app version uses English locale (i.e. it uses a dot as a decimal separator) even if you choose a non-English locale (i.e. one that uses a comma as a decimal separator).
Tablet-capable! App tested on Nexus 7 and Android 4.4.2 Kit Kat.