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Physics Calculators ▶ Gear Ratio Calculator

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**Table of Content**

Use this gear ratio calculator rpm to calculate gear ratio and mechanical advantage that it produces in a mechanical system. Moreover, you could also calculate the system torque, transmission mechanical speed of the tyre along with its diameter. So if you are up to buying a new car, you should have a proper knowledge of the overall gear speed and average it will produce to drive it. And this could be possible only if you give a read to the following article below.

Let’s start!

In the context of physics:

**“A particular wheel that alters the various physical parameters (direction, torque, and speed) related to its rotational motion is known as gear”**

Gears come in different shapes and sizes. But the overall shape remains circular because the gear calculations are totally dependent on its circumference. Anyhow, moving towards the gear types as mentioned under:

A driven gear that transmits power to the output gear or source is called input gear. The input gear is always connected to a power source.

The gear that is operated or rotated by the power provided by the input gear is called output gear.

A special mechanical structure in which two or more gears work together in a meat is

known as the gear train. Look at the figure below:

In this figure, there are two gears working together to produce rotational torque. The input gear is connected to the motor while the output gear is connected to the shaft to carry out the function. You should keep in mind that both the gears rotate in opposite directions to smooth the process. And if you want to calculate the exact clockwise or anticlockwise rotation, you may use the rotation calculator.

One more important factor regarding motion of gears is that you must look for the motion direction. Now this direction may or may not be the same for different types of machine gears. Below we have given a pictorial view of rotational axes for different kinds of gears.

Simply put:

**“The overall ratio of the input and the output gear based on their circumference is called gear ratio”**

The best way to determine the gear ratio is by utilising this online transmission gear ratio calculator. But we will also be taking you through the manual computational equations required to carry out the maths.

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

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

The above expression relates the circumference of the input gear to that of the output gear. Moreover, we have also designed another swift circumference calculator that lets you calculate the circumference of the circle in a matter of seconds.

**When only diameters or radii are taken into account:**

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

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

The rear gear calculator also determines the results depending upon various input parameters.

**When Input and Output Gear Teeth are taken into Account:**

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

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**

You can adopt various easy to express the mathematical form of the gear ratio. These may include:

As fractions are also ratios, you can express the gear ratio as the fractional numerals.

As the name signifies itself, the ratio is the comparison that is used to define the relative working of the gear’s teeth. You can better judge it by using this transmission gear ratio calculator.

A decimal depiction of the gear ratio reveals how much revolution of the input gear you actually need to get full revolution of the output gear.

In this section of the article, we will be taking you through the effect of the gear ratio on gear themselves.

Let us suppose we have a gear train in which two gears are associated to mount and scroll over each other. The input gear is small, having 10 teeth. While on the other hand, the output gear is bigger, consisting of 40 teeth. To better determine their corresponding ratio, you may subject to this rear end gear ratio calculator rpm.

Now if we talk about the gear ratio of both the gears, these are given as:

**10/40 = 10:4 = 0.25**

This illustrates that the four complete revolutions of the input gear will be sufficient to produce 1/4th of the output gear revolution. To relate these velocities better, we recommend you using the gear ratio calculator.

A particular gear that is inserted among input and output gears and changes the direction of revolution for the output gear is known as the idler gear.

Look at the figure below in which an idler gear has been installed in a gear train.

…

Now if the rotation of the output gear is clockwise, then this idler gear will change its rotation to counter clockwise and vice versa. Moreover, you may like to utilise our best rear gear calculator so as to calculate the actual gear ratio this idler gear would be producing among input and output gear.

Now the important factor to consider here is that the diameter of the tire is one of the most crucial factors that affect the gear ratio. If you are about to change your vehicles tyre of a considerable tire diameter, then you may get help from the following gear ratio chart:

TIRE DIAMETER |
GEAR RATIO | |||||||||||||||||

25″ |
2385 |
2568 |
2682 |
2804 |
2892 |
2988 |
3101 |
3259 |
3416 |
3590 | 3730 | 3984 | 4263 | 4482 | 4621 | 4700 | 4988 | 5390 |

26″ |
2293 | 2470 |
2579 |
2696 |
2780 |
2873 |
2982 |
3133 |
3284 |
3452 |
3587 | 3830 | 4099 | 4309 | 4444 | 4519 | 4796 | 5183 |

27″ |
2208 | 2378 |
2483 |
2597 |
2677 |
2766 |
2872 |
3017 |
3163 |
3325 |
3454 |
3689 | 3947 | 4150 | 4279 | 4352 | 4619 | 4991 |

28″ |
2129 | 2293 | 2395 |
2504 |
2582 |
2668 |
2769 |
2909 |
3050 |
3206 |
3331 |
3557 | 3806 | 4001 | 4126 | 4196 | 4454 | 4813 |

29″ |
2056 | 2214 | 2312 | 2417 |
2493 |
2576 |
2674 |
2809 |
2945 |
3095 |
3216 |
3434 |
3675 | 3863 | 3984 | 4052 | 4300 | 4647 |

30″ |
1987 | 2140 | 2235 | 2337 | 2410 |
2490 |
2584 |
2715 |
2846 |
2992 |
3109 |
3320 |
3553 | 3735 | 3851 | 3917 | 4157 | 4492 |

31″ |
1923 | 2071 | 2163 | 2261 | 2332 | 2409 |
2501 |
2628 |
2755 |
2896 |
3008 |
3213 |
3438 |
3614 | 3727 | 3790 | 4023 | 4347 |

32″ |
1863 | 2007 | 2095 | 2191 | 2259 | 2334 | 2423 |
2546 |
2669 |
2805 |
2914 |
3112 |
3331 |
3501 |
3610 | 3672 | 3897 | 4211 |

33″ |
1807 | 1946 | 2032 | 2124 | 2191 | 2263 | 2349 | 2469 |
2588 |
2720 |
2826 |
3018 |
3230 |
3395 |
3501 |
3561 | 3779 | 4083 |

34″ |
1754 | 1889 | 1972 | 2062 | 2126 | 2197 | 2280 | 2396 |
2512 |
2640 |
2743 |
2929 |
3135 |
3295 |
3398 |
3456 |
3668 | 3963 |

35″ |
1704 | 1835 | 1916 | 2003 | 2065 | 2134 | 2215 | 2328 | 2440 |
2565 |
2664 |
2845 |
3045 |
3201 |
3301 |
3357 |
3563 | 3850 |

36″ |
1656 | 1784 | 1862 | 1947 | 2008 | 2075 | 2154 | 2263 | 2372 |
2493 |
2590 |
2766 |
2961 |
3112 |
3209 |
3264 |
3464 |
3743 |

37″ |
1611 | 1735 | 1812 | 1895 | 1954 | 2019 | 2095 | 2202 | 2308 | 2426 |
2520 |
2692 |
2881 |
3028 |
3123 |
3176 |
3370 |
3642 |

38″ |
1569 | 1690 | 1764 | 1845 | 1902 | 1966 | 2040 | 2144 | 2247 | 2362 |
2454 |
2621 |
2805 |
2948 |
3040 |
3092 |
3282 |
3546 |

39″ |
1529 | 1646 | 1719 | 1798 | 1854 | 1915 | 1988 | 2089 | 2190 | 2302 | 2391 |
2554 |
2733 |
2873 |
2962 |
3013 |
3198 |
3455 |

40″ |
1491 | 1605 | 1676 | 1753 | 1807 | 1867 | 1938 | 2037 | 2135 | 2244 | 2331 | 2490 |
2664 |
2801 |
2888 |
2937 |
3118 |
3369 |

41″ |
1454 | 1566 | 1635 | 1710 | 1763 | 1822 | 1891 | 1987 | 2083 | 2189 | 2275 | 2492 |
2599 |
2733 |
2818 |
2866 |
3042 |
3287 |

42″ |
1420 | 1529 | 1596 | 1669 | 1721 | 1778 | 1846 | 1940 | 2033 | 2137 | 2220 | 2371 |
2538 |
2668 |
2751 |
2798 |
2969 |
3208 |

43″ |
1387 | 1493 | 1559 | 1630 | 1681 | 1737 | 1803 | 1894 | 1986 | 2087 | 2169 | 2316 | 2479 |
2606 |
2687 |
2733 |
2900 |
3134 |

44″ |
1355 | 1459 | 1524 | 1593 | 1643 | 1698 | 1762 | 1851 | 1941 | 2040 | 2119 | 2263 | 2422 |
2545 |
2626 |
2670 |
2834 |
3063 |

The interesting fact to consider here is that our free gear ratio speed calculator also does calculations for your tyre gear average by taking the above transmission table values as a standard.

In this section, we will guide how you could operate this calculator by entering the following inputs:

**Inputs:**

**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:**

- From the drop-down list, select the transmission mode
- Now enter the Engine RPM (Revolutions per minute), Axle Ratio, and Tire height in respective fields
- Likewise, go for entering the Tire Width, Wheel Diameter, and Aspect Ratios in their designated fields
- After you are done, hit the calculate button

**Output:**

The free gear ratio speed calculator does the following calculations:

- Gear ratio (for 1-6 gears)
- Mechanical advantage
- Rotational speed and torque of gear axle
- Width and height of the tire
- Miles per Hour for a gear speed

Here you can also use our free angular velocity calculator to calculate the circular speed of a physical object moving.

Normally, a 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.

Typically considered, a short gear ratio provides a greater speed. On the other hand, the shorter gear ratio provides you with the greater acceleration only in a specific direction.

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.

3.73 is the optimal gear ratio that produces a heavier torque required to drag a heavy truck like vehicle. Usually, a greater axle ratio allows the axle to provide rear wheel (in case of a motorcycle) and front wheels (in case of a car) with more torque for smooth drive. Moreover, this online gear speed calculator will help you straightaway in determining the torque to move your car’s axle.

In actual, the gear ratio 7.1:1 is used mostly for swim jigs in warmer weather, Froggin’, deep jigs, Flippin’, soft plastic stickbaits, topwater and late season jerkbaits.

A higher gear ratio is one with a short numerical number. The lower your gear ratio, the higher would be the amount torque provided by it that you can keep calculating with a torque calculator for free.

Gear ratios are very important in estimating the overall performance of your ride’s gear axle. When you calculate the gear ratio with our best transmission gear ratio calculator, you actually get half of the information required to determine the overall speed range of your ride.

From the source of Wikipedia: Gear train, Mechanical advantage, Analysis using virtual work, Gear trains with two gears, Double reduction gear, Speed ratio, Idler gears, Belt drives

From the source of Khan Academy: Simple machines and how to use this tutorial, Lever, Wheel, pulleys

From the source of Lumen Learning: Simple Machines, Forces and Torques