# What is a gear ratio? - Basic Mechanical Engineering

Q.  What is meant by gear ratio?
- Published on 01 Sep 15

a. The ratio of pinion speed and gear speed
b. The ratio of number of teeth on pinion and number of teeth on gear
c. Both a. and b.
d. None of the above

ANSWER: The ratio of pinion speed and gear speed

#### Discussion

• Sravanthi   -Posted on 06 Nov 15
- Speed or gear ratio is defined as the ratio of pinion speed and gear speed. It can also be defined as the ratio number of teeth on gear and number of teeth on pinion.

i = np / ng or i = zg / zp

here,

np = speed of pinion

ng = speed of gear

zg = number of teeth on pinion

zp = number of teeth on gear

- Gears are used to transfer power or motion from one part to another.

- A wheel having less number of teeth is called as pinion and with more number of teeth is called as gear.

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