Spicer Gear Ratio Calculator (2024)

FAQs

How do I figure out what gear ratio I need? ›

Calculate Ring & Pinion Teeth

Start counting! Count all the teeth on the pinion gear and the ring gear. Once you have those two numbers, divide the number of teeth that are on the ring gear by the number of teeth that are on the pinion gear and BAM–you have your gear ratio!

The calculation uses the number of teeth in the ring gear and divides it by the number of teeth in the pinion gear to provide you with a “[result] to 1” ratio. For example, if the pinion gear has 41 teeth, and the ring gear has 11 teeth, the ratio would be calculated as 41/11, which is equal to 3.73 = 3.73:1.

We can express this basic concept with the formula Gear ratio = T2/T1, where T1 is the number of teeth on the first gear and T2 is the number of teeth on the second.

Closer ratio cassettes such as 11/25, 11/28 or 11/30 are better for riders with a high level of fitness or who prefer flatter terrain. 1x systems are equipped with cassettes that have a much wider spread - anything between 11-42 and 10-50 at the norm.

Is it better to have a higher or lower gear ratio? A higher gear ratio is good when you need more acceleration to cruise your vehicle, whereas a lower gear ratio provides more torque to get the vehicle moving from a resting position.

If you are comparing one data point (A) to another data point (B), your formula would be A/B. This means you are dividing information A by information B. For example, if A is five and B is 10, your ratio will be 5/10. Solve the equation. Divide data A by data B to find your ratio.

It provides the equation to calculate gear ratio as the number of teeth on the input gear divided by the number of teeth on the output gear. In the example given, the input gear has 24 teeth and the output gear has 48 teeth, so the gear ratio is 0.5 or 1:2 based on the number of teeth.

Step 2: Count the Teeth on Each Gear

Once you have identified the driving and driven gears, count the number of teeth on each gear. The accuracy of your gear ratio calculation directly depends on this count, so ensure accuracy and refer to any schematics or data sheets for an accurate count.

To calculate the overall gear ratio of a compound gear train, find the gear ratio of each pair of meshing gears and then multiply the gear ratios together: Overall Gear Ratio = (Teeth on Driven Gear 1 / Teeth on Driver Gear 1) × (Teeth on Driven Gear 2 / Teeth on Driver Gear 2) × ...

Gear ratio calculation involves determining the ratio of the rotational speeds or torques between two intermeshing gears. It helps in understanding the relationship between the sizes and number of teeth on the gears, allowing engineers to design systems with desired speed or torque requirements.

Do gear ratios add or multiply? ›

The compound gear ratio between the driven and driv- ing gears is then calculated by multiplying the gear ratios of each of the individual gear pairs.

To calculate the gear ratio:

Divide the number of driven gear teeth by the number of drive gear teeth. In our example, it's 28/21 or 4 : 3. This gear ratio shows that the smaller driver gear must turn 1,3 times to get the larger driven gear to make one complete turn.

Rotate the marked tire one revolution while counting how many times the driveshaft rotates. eg, If your driveshaft made 3 3/4 revolutions, that would determine a 3.73 gear ratio. If you get approximately 2 3/4 revolutions, you have a 2.76 gear ratio.

The gear ratio gives us an idea of how much an output gear is sped up or slowed down or how much torque is lost or gained in a system. We equipped this calculator with the gear ratio equation and the gear reduction equation so you can quickly determine the gear ratio of your gears.

You don't. That information is not contained in the VIN, UNLESS a specific model only gets one rear end ratio. VIN tells country of manufacture, vehicle make, class, engine type, size, date of manufacture, plant and serial number. That is the ONLY information contained by the VIN.

So an easy way to determine your actual gear ratio is to check the tag attached to the differential cover by the cover bolts. On the tag there should be some numbering such as 3.54 or 3.73, either of those numbers will give you the stock axle ratio.