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I've heard that cars parked on an incline should leave the car in either 1st gear or reverse, because this supposedly provides the most engine resistance should the wheels start turning.

But my question is: Wouldnt using a higher gear cause more resistance for the wheels, given that in a high gear each revolution of the wheel causes a greater number of revolutions in the engine than a lower gear would?

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  • $\begingroup$ try driving 80 km/h in first gear $\endgroup$
    – jsotola
    Jan 29 at 4:26

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given that in a high gear each revolution of the wheel causes a greater number of revolutions in the engine than a lower gear would?

It is exactly the other way around:

  • In a low gear, the engine makes many revolutions for one turn of the wheel. This provides more torque for acceleration.

  • In a high gear, the engine makes few revolutions for one turn of the wheel, this allows you to drive high speeds with relatively low engine RPM.

Hence, when you push a parked car that has engaged 1st gear, you will make the engine do many revolutions for a low speed of the car: The car provides more engine resistance than when it would have been in a higher gear.

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  • $\begingroup$ Many cars are in direct drive in top gear; the trans does not change rotation speed. Drive wheels turn at the axel ratio. So with a 3:1 axel, the drive wheels turn once when the engine turns 3 times. $\endgroup$
    – blacksmith37
    Jan 28 at 17:22

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