If the transmission is in first gear with a ratio of 2.5:1 and the rear axle has a ratio of 2:1, what is the overall gear ratio?

To determine the overall gear ratio, you need to multiply the transmission gear ratio by the rear axle gear ratio.

In this case, the transmission is in first gear with a ratio of 2.5:1, meaning that for every 2.5 revolutions of the input shaft (from the engine), the output shaft (to the rear wheels) makes 1 revolution. The rear axle ratio is 2:1, indicating that for every 2 revolutions of the driveshaft, the rear wheels make 1 revolution.

To find the overall gear ratio, you multiply the two ratios:

Overall gear ratio = Transmission ratio × Rear axle ratio

= 2.5 × 2 = 5.

Thus, the overall gear ratio is 5:1. This means that the engine needs to make 5 revolutions to rotate the wheels once, which is advantageous for achieving higher torque for acceleration.

Understanding this process is essential for manual transmission operation, as it allows drivers to manage engine power effectively in different driving situations.