Gear Ratio Calculator
Standard Gear Ratio
Calculated Gear Ratio
Vehicle Speed Calculator
Estimated Vehicle Speed
Understanding the Calculations
This tool provides two essential calculators for mechanical and automotive applications. Use them to understand the relationship between gears, engine speed, and vehicle velocity.
How the Gear Ratio Calculator Works
The standard gear ratio is a fundamental concept in mechanics. It’s the ratio between the number of teeth on two connected gears. The formula is:
Gear Ratio = Teeth on Driven Gear / Teeth on Driving Gear
- Driving Gear: The gear that receives power from the input source (e.g., the engine).
- Driven Gear: The gear that receives power from the driving gear and sends it to the output.
How the Vehicle Speed Calculator Works
This calculator estimates your vehicle’s speed based on several key factors. It’s especially useful for seeing how changes in tire size or axle ratio will affect your speed at a given RPM. The formula used is:
Speed (MPH) = (RPM × Tire Diameter) / (Axle Ratio × Transmission Ratio × 336.13)
The constant value 336.13 is a conversion factor that simplifies the equation to output the speed directly in miles per hour (MPH).
Frequently Asked Questions
What is a gear ratio?
A gear ratio is a direct measure of the ratio of the rotational speeds of two or more interlocking gears. It is calculated by dividing the number of teeth on the driven gear (output) by the number of teeth on the driving gear (input). This ratio determines how torque and speed are transmitted between the gears.
How do you calculate the gear ratio?
The formula to calculate the gear ratio is: Gear Ratio = Number of Teeth on Driven Gear / Number of Teeth on Driving Gear. Our calculator performs this calculation for you instantly.
What does a higher or lower gear ratio mean?
A higher (or ‘taller’) gear ratio (e.g., 2.73:1) provides a lower numerical value, resulting in lower engine RPM at a given speed, which can improve fuel economy. A lower (or ‘shorter’) gear ratio (e.g., 4.10:1) provides a higher numerical value, resulting in more torque multiplication for better acceleration but higher engine RPM.
Related Engineering Tools
If you found this tool useful, you might also be interested in our other calculators:
- Sprocket Speed Calculator – Calculate the speed and ratios for chain and sprocket systems.
- Vehicle Speed Calculator – A more detailed tool focused solely on vehicle speed calculations with various parameters.
A gear ratio is a comparison of the number of rotations of a driving gear to the number of rotations of a driven gear. It essentially describes how the speed and torque of a rotating shaft are altered when transmitted through a gear train. A higher gear ratio means the output shaft rotates slower but with more force (torque), while a lower gear ratio results in a faster but weaker output.
- Definition:A gear ratio is the relationship between the number of teeth on two meshing gears. It can also be expressed as the ratio of the rotational speeds of the input and output shafts.
- Calculation:To calculate the gear ratio, divide the number of teeth on the driven gear by the number of teeth on the driving gear. For example, a gear with 40 teeth driving a gear with 10 teeth has a gear ratio of 4:1 (40/10).
- Effect on Speed and Torque:
- High Gear Ratio: A high gear ratio (e.g., 4:1) means the output shaft will rotate slower than the input shaft, but with four times the torque. This is useful for applications needing high force, like climbing a steep hill.
- Low Gear Ratio: A low gear ratio (e.g., 1:4) means the output shaft will rotate faster than the input shaft, but with less torque. This is beneficial for applications needing high speed, like driving on a highway.
- Applications:Gear ratios are crucial in various mechanical systems, including vehicles, robotics, and machinery, allowing for optimized performance based on the specific needs of the task.