Gear Ratio Calculator

Gear ratio is the relationship between the number of teeth on two gears that are meshed together. It's calculated by dividing the number of teeth on the driven gear by the number of teeth on the driving gear. For example, if the driving gear has 12 teeth and the driven gear has 48 teeth, the gear ratio is 4:1.

Mechanical advantage refers to how much force is multiplied through the gear system. A gear ratio greater than 1:1 provides mechanical advantage by trading speed for torque. For instance, a 4:1 ratio provides 4 times the torque but at 1/4 the speed.

Higher gear ratios (numerically higher) provide more torque multiplication for better acceleration and climbing ability but limit top speed. Lower gear ratios allow higher top speeds but reduce acceleration and torque multiplication.

Gear ratio typically refers to transmission ratios between individual gears, while differential ratio (final drive ratio) is the gear reduction in the rear axle. The total drive ratio combines both transmission and differential ratios.

Larger tires effectively reduce the gear ratio by covering more ground per revolution, increasing top speed but reducing acceleration. Smaller tires have the opposite effect, acting like a higher gear ratio with more acceleration but lower top speed.

Racing applications often use lower ratios (2:1 to 3:1) for high speed, while heavy-duty applications use higher ratios (4:1 to 6:1) for maximum torque. Street vehicles typically use ratios between 3:1 and 4.5:1 for balanced performance.