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In Engineering / College | 2025-07-08

Explain how gear ratio affects torque and speed in a gear system. Support your answer with an example using a gear ratio of 1:3.

Asked by Michcardwell64661

Answer (2)

In a gear system, the gear ratio is a critical concept that affects both torque and speed. A gear ratio is defined as the ratio of the number of teeth on two meshing gears. It can be expressed as:
Gear Ratio = Number of teeth on driving gear Number of teeth on driven gear ​ .
Torque and Speed Relationship:

Torque: Torque is the rotational force applied to a system. In a gear system, if the gear ratio is greater than 1, the output torque increases, but the speed decreases. Conversely, if the gear ratio is less than 1, the output torque decreases, but the speed increases.

Speed: Speed refers to how fast the gears are rotating. In a similar way to torque, a greater gear ratio will result in a decrease in speed, while a smaller gear ratio will increase speed.


Example with Gear Ratio of 1:3:
Let's consider a gear system where the driving gear (input gear) has 10 teeth and the driven gear (output gear) has 30 teeth. This gives us a gear ratio of 1:3 (or 1 to 3).

Input gear (driving gear): When this gear performs one full rotation, the output gear will only complete 1/3 of a rotation.

Output gear (driven gear): This means the output gear rotates slower than the input gear because it has three times more teeth.

Torque: Because the output gear is larger, it produces more torque; specifically, it has three times the torque of the input gear, assuming no energy losses.

Speed: The output speed is 1/3 of the input speed, reflecting the fact that the driven gear makes fewer rotations compared to the driving gear.


In summary, a gear ratio of 1:3 increases the torque threefold while reducing the speed to one-third. This principle is useful in applications requiring increased force such as in car transmissions or other mechanical devices requiring a trade-off between speed and force.

Answered by MasonWilliamTurner | 2025-07-21

The gear ratio affects torque and speed in a gear system by determining how much torque is increased or how much speed is decreased based on the ratio of the teeth. A gear ratio of 1:3 increases the output torque by three times while reducing the speed to one-third. This principle is important in mechanical applications that need a balance between force and speed.
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Answered by MasonWilliamTurner | 2025-08-15