What happens to the number of teeth on the rear sprocket of a chain-and-sprocket if the engine does not change?

• A. The number increases
• B. The number remains unchanged
• C. The number decreases
• D. The sprocket becomes obsolete

Answer: (C)

When considering the relationship between the rear sprocket's number of teeth and the performance of the engine, if the engine's power and torque output remain constant, a decrease in the number of teeth on the rear sprocket will lead to a higher gear ratio. This adjustment allows the same engine output to produce greater wheel speed, which can enhance acceleration without necessitating an engine change.

This means that by decreasing the number of teeth, the gearing becomes lower, allowing the same power to achieve more motion at the wheels. Conversely, increasing the number of teeth would reduce acceleration and increase load on the engine, while leaving the number of teeth unchanged would not alter the gearing dynamics at all.

The assertion that the sprocket becomes obsolete is unrelated to the functional outcome of changing the teeth count in relation to engine performance, which is a distinct concept. Thus, adjusting the teeth count directly affects gearing and performance dynamics without impacting the engine itself.