What Gear Ratio Do I Need, this is a burning question if one is driving a car and altering some features like tier size regularly. Many do not know the importance of putting the car into the right gear while driving it. Concerning simple but crucial things like this one will save the engine and keep it healthy for a longer time. Also, one can have proper speed and driving experience with the right gear ratio.
Deciding the exact gear ratio will depend on some mathematical calculation if one has made some changes. For that, they will have to read through the article properly.
What Gear Ratio Do I Need?
In automotive nothing is harder and either is easier. Sometimes a simple question needs a complicated explanation. Also, the simplest-looking feature of the car needs a proper explanation with terms, theory, and mathematics to understand. When one is driving a car they need too many things in their head to drive safely and properly. That is why they need to know the correct gear ratio for their driving style and their car.
One may ask why it is important to know the gear ratio of a car. Well, putting the car into the right gear ratio will affect the overall performance of the car as well as the fuel economy of the car. Besides, if one put the car in the wrong gear ratio they will hear a clanking noise as if something is breaking inside the car. it will create extreme traction between the teethes of the metal gear. In simple words, one should put the gear between 25% and 50% of the gear.
If one put the wrong gear ratio in the car, that means the engine will have to work out of its optimal RPM. If one does not know, the gear ratio of any car will depend on the tier size and the rpm of the engine. Driving the car into too low or too high a gear ratio, the engine will get erosion as well as the axels of the car.
Sometimes people change the diameter of their tier and then put the car into the same gear ratio. That makes a huge crisis in the performance of the car mainly when the transmission is manual. Because an inch difference in the tier will alter the calculation of the gear ratio. We have already mentioned that if it is too high and too low, the engine will get affected in a harmful way.
Besides, the gear ratio of any car will determine the speed of the car. Different gear ratios will allow the drivers to have a different range of speed. Powering up the vehicle at such a speed that the gear cannot handle will cause serious damage to the metallic part of the system.
Luckily there are many ways to calculate and find out which gear ratio one will need. The hardest way to calculate it is based on the gear teeth of the car. The law to find out gear ratio based on the gear teeth is,
“Gear Ratio = (Input Gear Teeth Number / Output Gear Teeth Number)”
We mentioned that this calculation is hard because it is not normal for every car owner to know the gear teeth number. Maybe it will be easier for a mechanical person but not for the majority of people. That is why everyone prefers the easiest way to calculate which involved the tier size and RPM of the engine.
“Gear ratio= (RPM x Tire Diameter Inches) / (Final Drive Ratio x Transmission Gear Ratio x 336)”
In case one does not know the final drive ratio and transmission gear ratio, they can calculate it in a different way. The formula is,
Gear Ratio = (RPM X Tire Diameter) / (MPH X 336)
For example,
Let us imagine that we have a car that has a 3000 RPM engine with 21 inches tier. So, the gear ratio for 60 MPH speed will be
Gear Ratio = (3000 X 21) / (60 X 336)
=3.13
Let’s have a look at the table below illustrating some of the common gear ratios based on tier size and RPM.
Gear ratio | |||||||||||||||
Tier size | 3.31 | 3.42 | 3.55 | 3.73 | 3.91 | 4.11 | 4.27 | 4.56 | 4.88 | 5.13 | 5.29 | 5.38 | 5.71 | 6.17 | 7.17 |
27" | 2677 | 2766 | 2872 | 3017 | 3163 | 3325 | 3454 | 3689 | 3947 | 4150 | 4279 | 4352 | 4619 | 4991 | 5800 |
28" | 2582 | 2668 | 2769 | 2909 | 3050 | 3206 | 3331 | 3557 | 3806 | 4001 | 4126 | 4196 | 4454 | 4813 | 5593 |
29" | 2493 | 2576 | 2674 | 2809 | 2945 | 3095 | 3216 | 3434 | 3675 | 3863 | 3984 | 4052 | 4300 | 4647 | 5400 |
30" | 2410 | 2490 | 2584 | 2715 | 2846 | 2992 | 3109 | 3320 | 3553 | 3735 | 3851 | 3917 | 4157 | 4492 | 5220 |
31" | 2332 | 2409 | 2501 | 2628 | 2755 | 2896 | 3008 | 3213 | 3838 | 3614 | 3727 | 3790 | 4023 | 4347 | 5051 |
32" | 2259 | 2334 | 2423 | 2546 | 2696 | 2805 | 2914 | 3112 | 3331 | 3501 | 3610 | 3672 | 3897 | 4211 | 4894 |
33" | 2191 | 2263 | 2349 | 2469 | 2588 | 2720 | 2826 | 3018 | 3230 | 3395 | 3501 | 3561 | 3779 | 4093 | 4745 |
34" | 2126 | 2197 | 2280 | 2396 | 2512 | 2640 | 2743 | 2929 | 3135 | 3295 | 3398 | 3456 | 3668 | 3963 | 4606 |
35" | 2065 | 2134 | 2215 | 2328 | 2440 | 2565 | 2664 | 2845 | 3045 | 3201 | 3301 | 3357 | 3563 | 3850 | 4474 |
36" | 2008 | 2075 | 2154 | 2263 | 2372 | 2493 | 2590 | 2766 | 2961 | 3112 | 3209 | 3264 | 3464 | 3743 | 4350 |
37" | 1954 | 2019 | 2095 | 2203 | 2308 | 2426 | 2520 | 2692 | 2881 | 3028 | 3123 | 3176 | 3370 | 3642 | 4243 |
38" | 1902 | 1966 | 2040 | 2144 | 2247 | 2362 | 2454 | 2621 | 2805 | 2948 | 3040 | 3092 | 3282 | 3546 | 4121 |
39" | 1854 | 1915 | 1988 | 2089 | 2190 | 2302 | 2391 | 2554 | 2733 | 2873 | 2962 | 3013 | 3198 | 3455 | 4015 |
40" | 1807 | 1867 | 1938 | 2037 | 2135 | 2244 | 2331 | 2490 | 2664 | 2801 | 2888 | 2937 | 3118 | 3369 | 3915 |
41" | 1763 | 1822 | 1891 | 1987 | 2083 | 2189 | 2275 | 2429 | 2599 | 2733 | 2818 | 2866 | 3042 | 3287 | 3819 |
42" | 1721 | 1778 | 1846 | 1940 | 2033 | 2137 | 2220 | 2371 | 2538 | 2668 | 2751 | 2798 | 2969 | 3208 | 3728 |
43" | 1681 | 1737 | 1803 | 1894 | 1986 | 2087 | 2169 | 2316 | 2479 | 2606 | 2687 | 2733 | 2900 | 3134 | 3642 |
44" | 1643 | 1698 | 1762 | 1851 | 1941 | 2040 | 2119 | 2263 | 2422 | 2546 | 2626 | 2670 | 2834 | 3063 | 3559 |
These are all the information to illustrate so that one can find out the gear ratio they need. The measurement will be different from different RPM, tier sizes, and the speed of the tier. One can find out the ratio from the table, if it is not in the table, they can simply calculate it by the formula.
Conclusion
Hopefully, one has got all the information regarding the gear ratio for specific measurements. Though the gear ratio sounds simple the parts related to it are not. It will directly affect the fuel economy, speed, and performance of the engine. So, it is important to measure the accurate gear ratio and put the car on it is necessary. Hopefully, all the theories and formulas will help me find out the answer to What Gear Ratio Do I Need?