What size rear axle is a 4.875 ratio?
4 Answers
4.875 ratio corresponds to a 158 rear axle. Here are the details: 1. Content: 4.875 is a low-speed axle. The rear axle ratio is an important engine parameter, referring to the gear ratio of the main reducer in the vehicle's drive axle. There is a set of gears in the rear axle behind the driveshaft that serves to reduce speed and increase torque. The vehicle's transmission ratio, also called the speed ratio, is the ratio of rotational speeds between the front and rear transmission mechanisms in the vehicle's drivetrain. The rear axle refers to the assembly that transmits power to the rear drive wheels, supporting the wheels and connecting the rear wheel assemblies. 2. Advantages: A smaller rear axle ratio provides higher speed and lower fuel consumption. The 4.875 ratio is suitable for heavy loads and offers good power performance.
The 4.875 gear ratio doesn't refer to the size of the rear axle, let me explain as someone who's driven for decades. Rear axle size typically means the ring gear diameter, common sizes being 8.5 inches or 9.5 inches - this depends on the vehicle model, like trucks or SUVs using larger axles to handle heavy loads. The 4.875 gear ratio is a proportion in the differential showing how many wheel rotations occur per engine revolution. Higher numbers mean more engine rotations per wheel turn - great for climbing or towing (more torque but slower speed), but unrelated to physical size. Check your vehicle manual or ask a dealer for exact axle dimensions to avoid mistakes that could damage your vehicle.
As an off-road enthusiast, I often use a high gear ratio like 4.875 for the rear axle, which increases torque and is suitable for off-road conditions. The size of the rear axle isn't determined by the gear ratio, but rather by the ring gear size. For example, light trucks commonly use 8.25-inch axles, while heavy-duty trucks might go up to 10 inches. This 4.875 ratio is ideal for steep slopes or muddy terrain, making it easier for the wheels to gain traction, but it increases fuel consumption at high speeds. When choosing a rear axle, you need to strike a balance: higher ratios make the vehicle more robust, but the axle must be sturdy enough. From my experience, I recommend test-driving extensively—listening to the engine sound will tell you if it's suitable, don't just rely on the numbers.
As a new car owner, I was also curious about this. A gear ratio of 4.875 is a high value, meaning more engine power is delivered to the wheels at slower speeds, which is suitable for vehicles that need quick acceleration. Rear axle sizes are typically measured by the ring gear diameter, such as 7.5 inches or 9.5 inches, commonly found in SUVs or pickup trucks. The 4.875 doesn't refer to the axle size but is a ratio parameter. I looked it up online—it tends to provide strong torque at low RPMs but consumes more fuel during high-speed cruising. To change the gear ratio, you first need to confirm your vehicle's original rear axle type to avoid issues. The simplest way is to have a mechanic check the manual for a safer approach.
