# What Are Gear Ratios? A vehicle’s gear ratio plays an important role in how fast your car will be able and how hard it will have to work to get there. Car manufacturers work to figure out the most efficient way to get speed while also focusing on the benefit of fuel economy for you. Here’s what you should know about gear ratios.

### What Are Gear Ratios?

In general, a vehicle’s engine and transmission contain a lot of gears. Gears are sets of toothed wheels that work together to alter the relation between the speed of a vehicle’s engine and the speed of the tires. The teeth in the gears make it possible to determine gear ratio. A vehicle’s gear ratios are what determine its top speed, how fast the vehicle can reach that speed, and how much work it will take to get there.

### How Do Gear Ratios Work?

Large gear ratios, such as in vehicles, are called gear trains. There are two sets of gear ratios in cars: the transmission gear ratio and the rear end/differential gear ratio. The transmission uses gear ratios to keep your engine running at a safe and economical RPM (revolutions per minute) range. At the same time your vehicle will be able to accelerate and maintain speed safely. Adding an additional gear to the transmission would allow it to keep accelerating and maintain speed at a lower and more efficient RPM.

Differential gear ratio determines the number of times the drive shaft will rotate for each turn of the wheels. When you change gear ratios, the RPM and the torque will change, but horsepower will not change. Torque is the amount of turning power. Torque is what will determine the acceleration of your car. When the large gears drive the small gears, this results in an increase in torque. When the small gears drive the large gears, torque will be decreased. Different vehicle manufacturers have different gear ratios.

### Gear Ratios by the Numbers

If you understand the circumference of a circle, you can begin to understand gear ratios. The circumference of a circle is equal to the diameter of the circle multiplied by Pi. If a gear has a diameter of one inch, the circumference of the gear is 3.14159.

To calculate torque gear ratio, you would divide the second gear’s ratio by the first gear’s ratio. If a driven gear has 56 teeth and a driver gear has 15 teeth. Dividing the driven gear by the driver gear gives you 3.73 and this means that the drive shaft turns 3.73 times for every turn of the wheel.

This would be known as 3.73:1. The lower the number, the faster the car will go with the same number of engine revolutions. The higher the number, the accelerate. A gear ratio that is numerically high is actually called a low gear. And a low gear ratio would be called high gear.

Gear ratios are a crucial part of your car’s performance. You want to be able to drive at whatever speed suits your environment while being as economical as possible, which leads to money savings for you. Car manufacturers do their best to make this happen.