| Axle Ratio | Axle Torque |
|---|
What Axle Torque Is
Axle torque is the twisting force delivered to the axle shafts after the differential does its work. The differential takes the torque arriving on the driveshaft and multiplies it by the axle ratio, the ring-and-pinion reduction, minus a little friction. It is the last stage of torque multiplication before the wheels, and it is what the axle shafts and their components must withstand.
How the Differential Splits It
An open differential divides axle torque equally between the two wheels, which is fine until one tire loses grip and both get only what the slipping wheel can hold. A limited-slip or locking differential can bias the torque toward the wheel with traction, sending far more than half to one side. That is why diff choice matters as much as raw torque for getting power down.
Sizing Axles and Components
Because the axle ratio multiplies torque, a numerically higher ratio raises the load on axle shafts, the ring and pinion, and the diff itself. Builders use axle torque to check that shafts and gears are strong enough for the engine and gearing, especially with sticky tires or heavy towing that prevent the wheels from spinning and relieving the load.
Frequently Asked Questions
Is axle torque the same as wheel torque?
They are closely related. Axle torque is the value at the differential output; wheel torque is the same energy expressed at the tire, often with the resulting tractive force.
Why does a locked diff stress one shaft more?
Because it can route nearly all the axle torque to a single wheel when the other lifts or slips, loading that one shaft far beyond the open-diff half.
How do I get driveshaft torque?
Multiply engine torque by the transmission gear ratio in use. The helper does this for you to carry it through to the axle.