Why do cars need transmissions?
Show answer & explanation
Answer: Match engine power to wheel speed
Transmit fuel to the engine — Wrong. The fuel system delivers fuel, not the transmission. Transmissions change the torque/speed relationship between engine and wheels.
Match engine power to wheel speed ✓ — Correct! Engines work best in a narrow speed range (RPM), but wheels need to turn at many different speeds. Transmissions use different gear ratios to match engine output to wheel needs—low gears give more power for starting/hills, high gears allow efficient cruising.
Cool the engine during driving — Wrong. The cooling system manages engine temperature. Transmissions change gear ratios to improve power delivery at different speeds.
Go deeper: Gear ratio
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