Gear ratio is the relationship between the number of teeth on the front (driver) sprocket and the rear (driven) sprocket. It tells you how many times the engine shaft rotates for every one rotation of the rear wheel. A higher ratio gives more torque and acceleration but reduces top speed. A lower ratio sacrifices low-end pull for higher top speed.
This calculator works for both sprocket systems (teeth count) and pulley systems (diameter) used in go-karts, minibikes, and small engines.
Divide the rear sprocket teeth by the front sprocket teeth. Example: 60 rear teeth / 12 front teeth = 5.0 : 1 gear ratio. This means the engine turns 5 times for every 1 turn of the rear wheel.
For racing go-karts, a ratio between 5:1 and 6:1 is common for short tracks. Longer tracks or higher top speeds call for lower ratios around 4:1 to 4.5:1.
Most stock minibikes run around 5:1 to 6:1. Performance builds often drop to 4:1 to 4.5:1 for more top speed.
Yes. A lower gear ratio (smaller number) increases top speed but reduces torque and acceleration. A higher ratio does the opposite.
They work the same way mathematically, but sprocket ratios use tooth count while pulley ratios use diameter. Both are calculated by dividing driven by driver.
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