How do you determine rear axle gear ratio?
How do you determine rear axle gear ratio?
Turn the wheel TWO revolutions and count the number of driveshaft turns. The number of driveshaft rotations will help you determine your rear axle ratio. For example, if it turned 3 and a half times, it’s a 3.50:1 ratio. If it turned 4 and a quarter times, it’s a 4.25:1 ratio.
What is a 3.42 rear axle ratio?
Axle ratios may be expressed in notation as something along the lines of “3.42:1,” or a “3.42 rear axle.” In either case, it essentially means the drive shaft and pinion need to rotate 3.42 times in order to rotate the axle shafts once.
What do you need to know about axle gear ratio?
People who are buying a used vehicle, or shopping for an axle from a junk yard, frequently need to know what the ring and pinion gear ratio is in the axle’s differential, as well as whether or not the axle has some sort of traction control device like a limited slip, locker, or spool.
How does gear ratio affect speed and torque?
When the rear end gear ratio is 1:1, the amount of speed and torque is similar. Therefore, when you increase the axle ratio, you reduce the amount of torque and significantly increase speed, and if you reduce the axle ratio, you reduce speed and boost the torque.
What happens to a truck with a low axle ratio?
A truck with a low axle ratio number means the vehicle will go faster and improved fuel economy, but lower towing capacity. The vehicle’s engine will work less when speeding on highways.
What’s the difference between high and low gear ratios?
Higher gear ratios (lower numerical axle ratio) provide better acceleration/torque, and lower gear ratios allow higher top speeds and better fuel economy. A vehicle with a high gear ratio runs faster to produce more power and achieve a given speed. Lower gear ratios ensure the engine runs more economically to maintain a given speed.
How can I find out my axle gear ratio?
One way is to look at the little metal tag that’s bolted to the differential cover. This will have stamped in it, among other things, either the gear ratio or the ring/pinion tooth counts that the axle came with from the factory. Tooth counts will be something like “ 37 9 ” for 4.11 gears (37 / 9 = 4.11).
What’s the gear ratio on a two wheel drive car?
Turn the wheel 2 complete turns. – Count the turns on the drive shaft. If it takes about 2 and three-quarters turns, it’s around a 2.73 gear ratio. If it’s a little more than 3, you have 3.08s. If it takes about 3 and a quarter turns of the driveshaft, you have 3.23 or 3.25 gears. Very close to 3 and three-quarter turns, 3.70 or 3.73 gears.
What’s the gear ratio on a Posi car?
If you have a car with a posi or limited slip rear, jack up the car and get both rear tires off the ground. Now put your jackstands under the axle. Make a line on the pinion yoke and onto the rear end with chalk or a grease pencil.
What happens when you have a high axle ratio?
A truck with a high axle ratio number means more towing capacity, decreased fuel economy, and a lower top speed. More mechanical power of the engine’s available torque is sent to the rear tires , improving off-the-line acceleration and more power for pulling heavy trailers and hauling hefty loads.
