Gear Ratio Calculator

The Gear Ratio Calculator determines the gear ratio of the circumference and the vehicle's speed in any gear and any engine RPM for the best performance. This enables you to know the relationship between the speed and torque in a mechanical system. We've integrated this calculator with the gear ratio formula to find out the ratio of the gear.

What is Gear?

A gear is a rotating mechanical component with teeth designed to transmit power and motion by meshing with other gears or toothed parts. By using gears, you can change the rotational speed, direction, and torque that is applied to it.

What is Gear Ratio?

"The ratio between the rotational speed of the final and the initial gear"

The Gear ratio communicates the degree of speed alteration and the torque variation experienced by the output gear in the system. It enables you to know how fast your vehicle can go in each gear at different engine RPMs for top performance.

• A high gear ratio will result in a slower speed but higher torque.
• A low gear ratio will result in a higher speed but lower torque.

How To Calculate Gear Ratio?

Below are the gear ratio equations to calculate the gear ratio so, follow these for manual calculation.

Gear Ratio Equations:

Let’s have a look at the relative equations that you could use to calculate the gear ratio accurately.

Formula # 1: The expression relates the circumference of the input gear to that of the output gear.

Gear Ratio = (π * Diameter of Input Gear)/(π * Diameter of Output Gear)

Formula # 2: When only diameters is known:

Gear Ratio = (Diameter of Input Gear)/(Diameter of Output Gear)

Formula # 3: When Radius is known:

Gear Ratio = (Radius of Input Gear)/(Radius of Output Gear)

Formula # 4: When the circumference of Input and the circumference of Output number of Gear Teeth are taken into account:

Gear Ratio = (Input Gear Teeth Number * (Gear Thickness + Teeth Spacing)) / (Output Gear Teeth Number * (Gear Thickness + Teeth Spacing))

Formula # 5: For smooth running of the gear, the thickness of each tooth along with spacing must be the same. That is why we will vanish these parameters from the above equation:

Gear Ratio = Input Gear Teeth Number / Output Gear Teeth Number

Gear Ratio Example:

Suppose two-gear system in which the pinnion gear has 52 teeths and other ring gear consists of 14 teeths. So, find that what is the ratio between pinnion gear and ring gear. Answer:

Gear Ratio = Input Number of Gear Teeth / Output Number of Gear Teeth = 52 / 14 = 3.71:1

So, it is determined that 3.71:1 ratio is concluded for the number of teeth in which each gear needs to produce a desired output speed or torque.

Gear Ratio Chart:

Steps To Utilize The Calculator:

The gear ratio calculator finds the rate of mechanical advantage or disadvantage a gear train produces in the gear system.

Required Values:

For Simple Mode:

• Enter input and output gear teeth number
• Likewise, enter the rotational speed and torque
• At the end, hit the calculate button

For Advanced Mode:

• Enter the Engine RPM (Revolutions per minute), Axle Ratio, and Tire height in respective fields
• Likewise, enter the Tire Width, Wheel Diameter, and Aspect Ratios in their designated fields
• After you are done, hit the calculate button

Final Results:

• The gear ratio
• Mechanical advantage
• Rotational speed and torque of gear axle
• Width and height of the tire
• Miles Per Hour (MPH) for a gear speed

Additional Querries:

What is a good gear ratio?

Normally, the gear ratio lower than 4.56 is considered better for smooth running of the gear, and thus the whole machine. If you want your ride to run without no knocking sound, then you should keep utilising this online gear ratio rpm calculator to keep an idea of your ride’s good performance.

Which gear ratio provides best fuel economy?

To drive heavier truck like vehicles, you must go for choosing a low gear ratio as 3.0, 3.23, or 3.31. But when it comes to the city cars, the axle ratio is not so affected by the MPG.