What does the rear axle ratio of a truck mean?
2 Answers
The rear axle ratio of a truck refers to the gear transmission ratio of the main reducer in the truck's drive axle, which is equal to the ratio of the rotational angular velocity of the drive shaft to the rotational angular velocity of the axle's half-shaft. Below is relevant information about the rear axle ratio: Key Factors: The rear axle ratio is related to the gears. The power output from the engine and transmission acts on the drive shaft, which rotates to input power to the pinion gear of the main reducer, driving the ring gear of the main reducer to rotate, and then driving the half-shaft to rotate. Calculation Formula: The number of teeth on the driven gear of the main reducer divided by the number of teeth on the driving gear of the main reducer. Simply put, if the drive shaft rotates N times to drive the half-shaft to rotate once, then N is the rear axle ratio.
I've driven trucks most of my life and know rear axle ratios inside out. It's essentially the gear ratio in the rear axle that tells you how many times the engine turns for each wheel rotation. Take this example: with a high ratio number, say above 5.0, the truck has tremendous pulling power—it climbs hills and hauls heavy loads effortlessly. When I transported ore, this setup conquered many steep slopes. But the downside is the engine revs high at highway speeds, and fuel consumption skyrockets. With a low ratio, say below 3.0, you get better fuel efficiency and quieter operation on highways, but weak acceleration and struggling under heavy loads. I remember once choosing the wrong ratio—my truck struggled uphill with cargo until I switched to a higher ratio. My advice: when buying a truck, don't just look at engine size; match the ratio to your routes—higher for mountains, lower for flat roads. Regular maintenance like checking gear oil also affects performance stability.
